Effects of Compostable Packaging and Perforation Rates on Cucumber Quality During Extended Shelf Life and Simulated Farm-To-Fork Supply-Chain Conditions

Article Effects of Compostable Packaging and Perforation Rates on Cucumber Quality during Extended Shelf Life and Simulated Farm-to-Fork Supply-Chain Conditions

Abiola Owoyemi 1,2, Ron Porat 1,* and Victor Rodov 1

1 Department of Postharvest Science, ARO—the Volcani Center, P.O. Box 15159, Rishon LeZion 7505101, Israel; [email protected] (A.O.); [email protected] (V.R.) 2 The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel * Correspondence: [email protected]

Abstract: Cucumbers are highly perishable and suffer from moisture loss, shriveling, yellowing, peel damage, and decay. Plastic packaging helps to preserve cucumber quality, but harms the environment. We examined the use of compostable modiﬁed atmosphere packaging (MAP) with different perforation rates as a possible replacement for conventional plastic packaging materials. The results indicate that all of the tested types of packaging reduced cucumber weight loss and shriveling. However, compostable MAP with micro-perforations that created a modiﬁed atmosphere of between

16–18% O2 and 3–5% CO2 most effectively preserved cucumber quality, as demonstrated by reduced peel pitting, the reduced appearance of warts and the inhibition of yellowing and decay development. Overall, micro-perforated compostable packaging extended the storage life of cucumbers under Citation: Owoyemi, A.; Porat, R.; both extended shelf conditions and simulated farm-to-fork supply-chain conditions and thus may Rodov, V. Effects of Compostable serve as a replacement for the plastic packaging currently used to preserve the postharvest quality Packaging and Perforation Rates on of cucumbers. Cucumber Quality during Extended Shelf Life and Simulated Keywords: cucumber; modified atmosphere; postharvest; plastic; compostable Farm-to-Fork Supply-Chain Conditions. Foods 2021, 10, 471. https://doi.org/10.3390/ foods10020471 1. Introduction Academic Editor: Carmine Summo Fresh fruit and vegetables (F&V) are living organisms and, as such, are very perishable food items with relatively short postharvest storage lives [1]. According to the United Received: 2 February 2021 Nations (UN) Food and Agriculture Organization (FAO) report, about one-third of all food Accepted: 17 February 2021 produced on the planet gets lost and is not consumed by humans [2]. The F&V category Published: 20 February 2021 accounts for 44% of total global food losses [2,3]. Furthermore, the FAO reported that between 45 and 55% of all F&V produced worldwide is lost or wasted along the supply Publisher’s Note: MDPI stays neutral chain [2]. Most food losses in medium- and high-income countries occur at the retail and with regard to jurisdictional claims in consumption stages of the food supply chain [2,4]. According to a U.S. Department of published maps and institutional affil- Agriculture Economic Research Service (USDA-ERC) report, in the U.S. alone, fruit and iations. vegetables losses at the retail and consumption stages are estimated at 18.4 and 25.2 billion pounds, respectively, which represent losses of 28% of all fruit and 30% of all vegetables at these two stages [5]. Retail packaging is one of the key strategies for preserving food freshness and quality Copyright: © 2021 by the authors. and reducing food losses [6–8]. A recent study by the American Institute for Packaging Licensee MDPI, Basel, Switzerland. and the Environment proposed that proper use of packaging might reduce 10–15% of This article is an open access article food waste at the store level and 20–25% of food waste at the household level [9]. Be- distributed under the terms and sides its basic role of containing the food, a retail F&V package may create an optimized conditions of the Creative Commons modified-atmosphere and modified-humidity conditions to retain freshness, slow down Attribution (CC BY) license (https:// ripening and senescence processes, and reduce the development of decay and physiological creativecommons.org/licenses/by/ disorders [10,11]. The creation of an optimal atmosphere and optimal humidity conditions 4.0/).

Foods 2021, 10, 471. https://doi.org/10.3390/foods10020471 https://www.mdpi.com/journal/foods Foods 2021, 10, 471 2 of 14

within the retail packaging greatly depends on the respiration rate of the produce and storage temperatures, as well as on the gas permeability and perforation rates of the packaging. Macro-perforations (4- to 8-mm holes) allow for the free exchange of gases through the package and so do not support the creation of a modified atmosphere. In contrast, in sealed packages or packages with micro-perforations, which are typically 30–350 µm in size, we may find a modified gaseous composition within the package, which will vary with the amount and type of packed produce and storage temperatures [12,13]. Despite the great advantages of plastic packaging for preserving freshness and reducing food losses, today, its use has negative environmental connotations and encounters an unfavorable public attitude. Currently, most plastic packages are made of conventional polymers that are responsible for environmental pollution due to their very slow degradation kinetics [14]. To address the issue of plastic pollution, more than 400 organizations have recently signed the New Plastics Economy Global Commitment, which endorses a common circular economy vision according to which, by 2025, all plastic packaging will be reusable, recyclable or compostable [15]. The use of compostable polymers may provide a promising sustainable solution, provided that the packaging made from those polymers extends produce storage life at least as effectively as conventional plastic packaging [16–18]. In the current study, we examined the effects of compostable packages with different perforation rates on the quality of fresh cucumber fruits over time under different storage conditions. Cucumbers are highly perishable and are very susceptible to moisture loss, shriveling, yellowing and the development of physiological injuries, and microbial spoilage [19]. It was previously reported that conventional plastic modified-atmosphere packaging (MAP) effectively extends the storage life of cucumbers and alleviates the development of chilling injury in cucumbers [20–22]. Suslow and Cantwell [19] reported that cucumbers might tolerate relatively low O2 levels of 3–5%, but will not tolerate more than 10% CO2, and Manjunatha and Anurag [21] reported that the optimal gas conditions for MAP for cucumbers are between 12 and 17% O2, and 5 and 10% CO2. In this study, we examined the efficacy of compostable MAP for preserving cucumber quality and the use of such packaging as a possible replacement for the conventional plastic retail packaging currently in use.

2. Materials and Methods 2.1. Plant Material Cucumbers (Beit Alpha type) were harvested on 31 December 2019 from a commercial greenhouse in Ahituv, Israel, and brought within 1 h to the Department of Postharvest Science, Agricultural Research Prganization (ARO), The Volcani Center. There, the fruits were divided into 90 groups, with each group containing eight fruit that had a uniform green color. The fruit were distributed into ﬁve different packaging treatments as described below. Each treatment included 18 packages, with three packages for each evaluation point.

2.2. Packaging Treatments The experiment included ﬁve treatments: (1) control, (2) non-perforated compostable package, (3) micro-perforated compostable package, (4) macro-perforated compostable package, and (5) commercial macro-perforated polypropylene package. The packages made of a compostable polyester blend were 35 µm thick and 30 × 40 cm in size and were supplied by TIPA® Corp. (Hod HaSharon, Israel). The polypropylene packages of similar thickness and dimensions were supplied by R.O.P. Ltd. (Hahotrim, Israel). The oxygen transmission rates (OTR) of the compostable and polypropylene packages were 875 and 2019 cc/m2/day, respectively; and the water vapor transmission rates (WVTR) of the compostable and polypropylene packages were 40.8 and 8.1 gr/m2/day, respectively. Micro-perforations were made by making 8 holes with a 0.5-mm needle (PIC Ago Ipodermico, 25G hypodermic needle, Grandate, Italy) and macro-perforations were made by making 8 holes (6 mm in width) with a hole puncher commonly used to punch holes in paper. The bags were sealed using a manual impulse heat sealer (Swery Electronics Foods 2021, 10, 471 3 of 14

Ltd., Petah Tikva, Israel). Control, non-bagged fruits were kept in open rigid polyethylene terephthalate (PET) containers (Plasto-Vack, Rishon LeZion, Israel). The headspace oxygen and carbon dioxide concentrations in the packages were measured with an OxyBABY gas analyzer (WITT Gasetechnik GmbH and Co KG, Witten, Germany).

2.3. Storage Conditions The fruit were stored under two different regimes. The ﬁrst regime included continuous storage at 22 ◦C, to simulate the extended marketing period on a non-refrigerated shelf (“Extended shelf life”). The second regime simulated the farm-to-fork supply chain, including 2 days of distribution at 15 ◦C + 2 days of shelf life at 22 ◦C + 1 or 2 weeks of home storage at 4 ◦C in a 600-L home refrigerator (“Supply chain + home storage”). The relative humidity (RH) at the different storage rooms at 22, 15, and 4 ◦C was ~60%, ~75 and ~92%, respectively.

2.4. Quality Evaluations Quality evaluations were conducted at time zero and after 5, 10, and 15 days under shelf conditions (22 ◦C) and after exposure to simulated distribution and marketing conditions (2 days at 15◦C + 2 days at 22 ◦C) and 1 and 2 additional weeks of refrigerated home storage at 4 ◦C. Quality evaluations included measurements of fruit weight loss (percentage of initial weight) and visual estimations of water condensation on the packages, shriveling, peel pitting, and the appearance of warts (0 = none, 1 = slight, 2 = moderate, and 3 = severe). Peel color was evaluated according to a visual yellowing scale (0 = dark green, 1 = light green, 2 = green–yellow, 3 = mostly yellow). The incidence of microbial decay was measured as the percentage of infected fruit. Flavor was rated on a 9-grade hedonic scale, in which 1 = very bad and 9 = excellent. Finally, an overall visual-acceptance score was determined according to a 5-grade scale, in which 1 = very bad, 2 = poor, 3 = fair, 4 = good, and 5 = excellent. A score of 2.5 was deﬁned as the minimum acceptability threshold. All visual and sensory evaluation scores were assigned by three trained panelists.

2.5. Statistical Analysis One-way analysis of variance (ANOVA) and Tukey’s honestly signiﬁcant difference (HSD) pairwise comparison tests were applied using the JMP statistical software program, version 7 (SAS Institute Inc., Cary, NC, USA). Microsoft Ofﬁce Excel was used to calculate means, standard deviations and standard errors.

3. Results 3.1. Visual Appearance At time zero, the fruits were ﬁrm, had a dark green color and were free of blem- Foods 2021, 10, 471 4 of 15 ishes (Figure1). The polypropylene packages were clear and transparent, whereas the compostable packages were slightly hazy (Figure1).

FigureFigure 1. 1.Visual Visual appearance appearance of of control, control, compostable compostable and and polypropylene polypropylene packages packages of of cucumber cucumber fruit. fruit.

During the extended shelf-conditions at 22 °C, the quality of the control, non-packed cucumbers deteriorated quickly (Figure 2). After 10 days of shelf conditions, these fruits were shriveled and had a light green–yellowish color. In contrast, the cucumbers in all of the perforated packages remained smooth, green, and healthy, while those in the non- perforated packages suffered from decay (Figure 2). After 15 days of shelf conditions, the control fruit were severely shriveled and turned yellow–brown. The cucumbers in the macro-perforated packages, both the compostable ones and those made of polypropylene film, senesced and turned yellow; the cucumbers in the non-perforated compostable packages suffered from senescence and decay (Figure 2). At that time, only the cucumbers in the micro-perforated packages remained smooth and green.

Figure 2. Photographs of cucumber fruits stored in different types of packaging for (a) 10 days or (b) 15 days under continuous shelf conditions at 22 °C. COM—compostable, PP—polypropylene, µ—micro-perforated, M—macro-perforated, NP—non-perforated.

Quality loss was also evident among the control fruits during the supply-chain simulation and subsequent refrigerated home storage (Figure 3). After 1 week of refrigerated home storage, the control fruits were shriveled, but remained green; whereas the packaged fruits were still smooth and attractive. After 2 weeks of home storage, the control fruits were severely shriveled and had turned light green–yellowish; whereas the quality of the cucumbers packed in the micro-perforated compostable package remained adequate. The cucumbers in the macro-perforated packages were of medium quality and the cucumbers in the non-perforated packages were slimy and macerated due to bacterial spoilage (Figure 3).

Foods 2021, 10, 471 4 of 15

Foods 2021, 10, 471 4 of 14 Figure 1. Visual appearance of control, compostable and polypropylene packages of cucumber fruit.

During the extended shelf-cond shelf-conditionsitions at 22 ◦°C,C, the quality of the control, non-packed cucumbers deteriorated quickly (Figure 22).). AfterAfter 1010 daysdays ofof shelfshelf conditions,conditions, thesethese fruitsfruits were shriveled and and had had a a light light green–yellowish green–yellowish color. color. In In contrast, contrast, the the cucumbers cucumbers in inall allof theof the perforated perforated packages packages remained remained smooth, smooth, gr green,een, and and healthy, healthy, while while those those in in the the non- perforated packages packages suffered suffered from from decay decay (Figure (Figure 2).2). After After 15 15 days days of ofshelf shelf conditions, conditions, the controlthe control fruitfruit were were severely severely shriveled shriveled and and turned turned yellow–brown. yellow–brown. The The cucumbers cucumbers in the macro-perforated packages, both the compostable ones and those made of polypropylene film,ﬁlm, senesced senesced and and turned turned yellow; yellow; thethe cucumbers cucumbers in the in non-perforated the non-perforated compostable compostable packagespackages suffered suffered from from senescence senescence and anddecay decay (Figure (Figure 2). 2At). Atthat that time, time, only only the the cucumbers cucumbers in thein the micro-perforated micro-perforated packages packages remained remained smooth smooth and and green. green.

Figure 2. PhotographsPhotographs of of cucumber cucumber fruits fruits stored stored in in different different types types of of packaging packaging for for (a ()a 10) 10 days days or or (b) 15 days under continuous shelf conditions at 22 °C. COM—compostable, PP—polypropylene, (b) 15 days under continuous shelf conditions at 22 ◦C. COM—compostable, PP—polypropylene, µ—micro-perforated, M—macro-perforated, NP—non-perforated. µ—micro-perforated, M—macro-perforated, NP—non-perforated.

Quality loss was also evident amongamong thethe controlcontrol fruitsfruits duringduring thethe supply-chain supply-chain simu- sim- ulationlation and and subsequent subsequent refrigerated refrigerated home home storagestorage (Figure(Figure3 3).). After After 1 1 week week ofof refrigeratedrefrigerated home storage, the control fruits were shrive shriveled,led, but remained green; whereas whereas the the packaged fruits were still smooth and attractive. After 2 weeks of home storage, the control fruits were severely shriveled and had turn turneded light green–yellowish green–yellowish;; whereas the quality of the cucumbers packed in the micro-perforatedmicro-perforated compostable package remained adequate. The cucumbers in the macro-perforated packages were of medium quality and the cucumbers in the non-perforated packages we werere slimy and macerated due to bacterialbacterial spoilage (Figure 33).).

3.2. Atmosphere Compositions After 5 days of shelf life at 22 ◦C, as well as after the supply-chain treatment (2 days at ◦ ◦ 15 C + 2 days at 22 C), the O2 levels in the non-perforated compostable packages were extremely low (nearly 1.5%) and the CO2 levels in those packages had increased to nearly 7%. Later on, the O2 levels in the sealed compostable packages gradually increased to 16–17% and the CO2 levels gradually decreased to 4–5% (Figure4). In the micro-perforated

compostable packages, the O2 levels decreased moderately to just 15–17%, while the CO2 levels increased moderately to 2–5% (Figure4). The O 2 and CO2 levels in the macro- perforated packages were similar to those detected in regular air (Figure4). FoodsFoods 20212021,, 1010,, 471471 55 ofof 1415

Figure 3. Photographs of of cucumber cucumber fruits fruits stored stored in in different different types types of of packaging packaging under under simulated simulated farm-to-fork supply-chainsupply-chain conditionsconditions including including distribution distribution and and marketing marketing (2 (2 days days at at 15 15◦C °C + + 2 2 days days at 22 °C) plus (a) 1 week or (b) 2 weeks of refrigerated home storage at 4 °C. COM—com- at 22 ◦C) plus (a) 1 week or (b) 2 weeks of refrigerated home storage at 4 ◦C. COM—compostable, postable, PP—polypropylene, µP—micro-perforated, MP—macro-perforated, NP—non-perfo- PP—polypropylene, µP—micro-perforated, MP—macro-perforated, NP—non-perforated. rated. 3.3. Water Loss and Condensation 3.2. Atmosphere Compositions A major problem with cucumber preservation is extensive water loss after harvest. Our resultsAfter 5 indicateddays of shelf that life non-bagged, at 22 °C, as control well as fruits after lost the upsupply-chain to 39% of their treatment initial weight(2 days afterat 15 15°C days+ 2 days of storage at 22 °C), under the shelfO2 levels conditions in the non-perforated (22 ◦C) and up tocompostable 25% of their packages initial weight were afterextremely storage low under (nearly the 1.5%) simulated and the supply-chain CO2 levels in conditions those packages and 2had weeks increased of refrigerated to nearly home7%. Later storage on, the (Figure O2 levels5a,b). in the In contrast,sealed compostable the cucumbers packages in the gradually various increased packages to had 16– significantly17% and the (pCO≤20.05) levels lower gradually weight decreased loss, and lostto 4–5% only 13–20%(Figure of4). their In the initial micro-perforated weight under thecompostable shelf conditions packages, and the 5–9% O2 oflevels their decreased initial weight moderately after the to supply-chain just 15–17%, treatmentwhile the andCO2 twolevels additional increased weeks moderately of refrigerated to 2–5% home(Figure storage 4). The (Figure O2 and5a,b). CO2 levels in the macro-per- foratedCondensation packages were was similar minimal to thos in alle detected of the packages in regular kept air under(Figure shelf 4). conditions, but reached slight and moderate levels in the polypropylene packages after 1 and 2 weeks of refrigerated3.3. Water Loss home and storage,Condensation respectively. The condensation levels in all of the compostable packagesA major were problem significantly with (cucumberp ≤ 0.05) lower preservation at all of theis extensive evaluation water dates loss (Figure after5 harvest.c,d). Our results indicated that non-bagged, control fruits lost up to 39% of their initial weight 3.4. Peel Blemishes after 15 days of storage under shelf conditions (22 °C) and up to 25% of their initial weight after Beitstorage Alpha-type under the cucumbers simulated have supply-cha a smoothin conditions peel. However, and 2 after weeks harvest, of refrigerated the fruit mayhome suffer storage from (Figure water 5a,b). loss-related In contrast, shriveling the cucumbers and develop in the physiological various packages peel had blemishes, signif- suchicantly as ( pittingp ≤ 0.05) and lower warts. weight We found loss, and that lost the only control, 13–20% non-packed of their fruitinitial suffered weight from under more the shrivelingshelf conditions than the and packed 5–9% of fruit. their Under initial shelf weight conditions, after the thesupply-chain severity of treatment shriveling and among two theadditional control weeks fruits wasof refrigerated slight after home 5 days, storage slight to(Figure moderate 5a,b). after 10 days and severe after 15 days.Condensation All of the baggedwas minimal fruits in showed all of significantlythe packages (pkept≤ 0.05) under lower shelf values, conditions, and hadbut onlyreached slight slight shriveling and moderate (Figure levels6a). In in the the simulatedpolypropylene farm-to-fork packages storage after 1 regime,and 2 weeks barely of any shriveling was observed immediately after marketing (2 days at 15 ◦C + 2 days at refrigerated◦ home storage, respectively. The condensation levels in all of the compostable 22packagesC). However, were significantly after 1 and ( 2p weeks≤ 0.05) oflower subsequent at all of homethe evaluation refrigerated dates storage, (Figure the 5c,d). control fruit exhibited slight and moderate shriveling, respectively, while all of the packed fruits showed significantly (p ≤ 0.05) lower shriveling symptoms (Figure6b). Regarding pitting damage, only control fruits and fruits packaged in the non-perforated compostable packages showed slight but significantly (p ≤ 0.05) damage after 5 and 10 days under shelf conditions. However, after 15 days under shelf conditions, the control fruit suffered from severe pitting, while the fruit in the non-perforated and macro-perforated packages showed only slight to moderate damage. Fruits in the micro-perforated compostable packaging had the lowest pitting index (Figure6c). In the simulated farm-to-fork supply-chain regime, all of the fruits had very low pitting damage after been exposed to the simulated marketing conditions. However, after 1 week of refrigerated home storage,

Foods 2021, 10, 471 6 of 14

the control fruits and the fruits packed in the non-perforated compostable bags had signiﬁ- cantly (p ≤ 0.05) higher pitting damage, while there was only minimal damage among the fruits stored in the micro- and macro-perforated packages. After 2 weeks of home storage, the pitting damage was severe in the control fruit and moderate in the cucumbers kept in Foods 2021, 10, 471 6 of 15 non-perforated packages. All of the fruits kept in micro- and macro-perforated packages showed very little pitting damage (Figure6d).

FigureFigure 4. Oxygen 4. Oxygen and carbon and carbon dioxide dioxide levels in levels the he inadspaces the headspaces of different of different cucumber cucumber packages. packages. MeasurementsMeasurements were were taken taken during during continuous continuous storage storage under under shelf conditions shelf conditions at 22 °C at (Extended 22 ◦C (Extended shelfshelf life) life)and after and afterthe simulated the simulated farm-to-fork farm-to-fork suppl supply-chainy-chain treatment treatment (2 days (2 daysat 15 at°C 15 + 2◦ Cdays + 2 at days at 22 °C)22 plus◦C) plus 1 or 1 2 or weeks 2 weeks of refrigerated of refrigerated home home storage storage at at 4 4 °C◦C (Supply (Supply chain ++ homehome storage).storage). Figures Figures (a) and (b) represent O2 levels, and Figures (c) and (d) represent CO2 levels after extended (a) and (b) represent O2 levels, and Figures (c) and (d) represent CO2 levels after extended shelf shelf life and farm-to-fork supply-chain conditions, respectively. Data are means ± SE of 3 replica- life and farm-to-fork supply-chain conditions, respectively. Data are means ± SE of 3 replications. tions. Different letters indicate significant differences at p ≤ 0.05. COM—compostable, PP—poly- Different letters indicate signiﬁcant differences at p ≤ 0.05. COM—compostable, PP—polypropylene, propylene, µP—micro-perforated, MP—macro-perforated, NP—non-perforated. µP—micro-perforated, MP—macro-perforated, NP—non-perforated.

Extended shelf life Supply chain + home storage 50 a Regarding the appearance of warts,50 afterb 10 and 15 days of the extended shelf-life ◦ a 45regime (22 C), the control, non-packed fruit45 and the fruit packaged in macro-perforated 40 packages40 had signiﬁcantly (p ≤ 0.05) more warts, whereas the fruits in the non-perforated 35 (%) 35 30and micro-perforated compostable packages30 barely had any warts ata all (Figure6e). Similar 25 a b 25 trends were observed under the simulated farm-to-fork supply-chaina regime, in which the 20 b 20 b b 15developmenta of a warty appearance wasWeight loss prevented15 a by keeping the cucumbers under modi- Weight loss ( % ) ab 10 ab ab b b b 10 b bc ﬁed atmosphere conditions in non-perforated or micro-perforatedbc bc packages (Figure6f). 5 b b b b c b 5 b b b c 0 0 3.5. Peel51015 Color Market ing Market ing + 7d After Marketing + 14 d 3 c The cucumbers were dark green at3 harvest,d but tended to yellow during storage. Under continuous shelf conditions (at 22 ◦C), the control, non-packed fruit turned light a green–yellow2 after 10 days and yellow–brown2 after 15 days (Figures2 and7a). In contrast, all of the bagged fruits remained green after 10 days; but after 15 days, the green peel

a color1 was retained only among the cucumbers1 in the non-perforated and micro-perforated Condensation( 0-3) Condensation (0-3) Condensation compostable packages (Figures2 and7a). In the farm-to-forkb supply-chain simulation, all a a bc a a b b b of thea a fruitsa a remaineda a a a greena a aftera a the simulateda a marketinga a andc one additional week of re- 0 0 frigerated5d home storage. 10d However, 15d after 2 weeksSC of home SC storage, + 7d HS the SC + 14d control HS fruits as well as the fruits in the macro-perforated packages had turned light green; whereas the fruits in Control COM-NP COM-µP COM-MP PP-MP the sealed and micro-perforated packages remained mostly dark green (Figures3 and7b ). Figure 5. Weight loss and condensation levels in different cucumber packages. Measurements were taken during continuous storage under shelf conditions at 22 °C (Extended shelf life) and after the simulated farm-to-fork supply-chain treatment (2 days at 15 °C + 2 days at 22 °C) plus 1 or 2 weeks of home refrigerated storage at 4 °C (Supply chain + home storage). Figures (a) and (b) represent weight loss levels, and Figures (c) and (d) represent condensation levels after extended shelf life and farm-to-fork supply-chain conditions, respectively. Data are means ± SE of 3 replications. Different letters indicate significant differences at p ≤ 0.05. COM—compostable, PP—polypropylene, µP—micro-perforated, MP—macro-perforated, NP—non-perforated.

Foods 2021, 10, 471 6 of 15

Figure 4. Oxygen and carbon dioxide levels in the headspaces of different cucumber packages. Measurements were taken during continuous storage under shelf conditions at 22 °C (Extended shelf life) and after the simulated farm-to-fork supply-chain treatment (2 days at 15 °C + 2 days at 22 °C) plus 1 or 2 weeks of refrigerated home storage at 4 °C (Supply chain + home storage). Figures (a) and (b) represent O2 levels, and Figures (c) and (d) represent CO2 levels after extended Foods 2021, 10, 471 shelf life and farm-to-fork supply-chain conditions, respectively. Data are means ± SE of 3 replica-7 of 14 tions. Different letters indicate significant differences at p ≤ 0.05. COM—compostable, PP—polypropylene, µP—micro-perforated, MP—macro-perforated, NP—non-perforated.

Extended shelf life Supply chain + home storage 50 50 a a b 45 45 40 40

35 (%) 35 30 30 a 25 a b 25 a 20 b 20 b b 15 a Weight loss 15 a Weight loss ( % ) ab 10 ab ab b b b 10 b bc bc bc 5 b b b b c b 5 b b b c 0 0 51015 Market ing Market ing + 7d After Marketing + 14 d

3 c 3 d

2 2 a

a 1 1 Condensation( 0-3) Condensation (0-3) Condensation b a a bc a a b b b a a a a a a a a a a a a a a a a c 0 0 5d 10d 15d SC SC + 7d HS SC + 14d HS

Control COM-NP COM-µP COM-MP PP-MP

FigureFigure 5. 5. WeightWeight loss loss and and condensation condensation levels levels in in different different cucumber cucumber packages. packages. Measurements Measurements were weretaken taken during during continuous continuous storage storage under under shelf shel conditionsf conditions at at 22 22◦C °C (Extended (Extended shelf shelf life)life) andand after afterthe simulatedthe simulated farm-to-fork farm-to-fork supply-chain supply-chain treatment treatmen (2t (2 days days at at 15 15◦C °C + + 2 2days days atat 2222 ◦°C)C) plus 1 1 or or2 2 weeks weeks of of home home refrigerated refrigerated storagestorage atat 44 ◦°CC (Supply chain chain + + ho homeme storage). storage). Figures Figures (a) ( aand) and (b) ( b) representrepresent weight weight loss loss levels, levels, and Figures ((cc)) andand ((dd)) represent represent condensation condensation levels levels after after extended extended shelf shelf life and farm-to-fork supply-chain conditions, respectively. Data are means ± SE of 3 replica- life and farm-to-fork supply-chain conditions, respectively. Data are means ± SE of 3 replications. tions. Different letters indicate significant differences at p ≤ 0.05. COM—compostable, PP—poly- Different letters indicate signiﬁcant differences at p ≤ 0.05. COM—compostable, PP—polypropylene, propylene, µP—micro-perforated, MP—macro-perforated, NP—non-perforated. µP—micro-perforated, MP—macro-perforated, NP—non-perforated.

3.6. Decay Development After 10 days under continuous shelf conditions (22 ◦C), the fruit in the non-perforated packages showed a signiﬁcantly (p ≤ 0.05) increase of up to 75% decay and the incidence of decay in these packages reached 100% after 15 days of shelf conditions. At the same time, the control fruits and the fruits in the macro-perforated packages developed between 40 to 70% decay, while the fruit in the micro-perforated packages did not show any decay at all (Figure7c). In the farm-to-fork supply-chain regime, there was no decay after the marketing simulation. However, after one additional week of refrigerated home storage, the control, non-bagged fruit showed 12.5% decay. After 2 weeks of refrigerated home storage, the level of decay among the control fruits and the fruits in the non-perforated packages reached 37.5%, while there was a negligible incidence of decay among the fruits in the micro-perforated and macro-perforated packaging (Figure7d).

3.7. Fruit Flavor The flavor-acceptance score was 7.5 at harvest (on a scale of 1 to 9) and decreased during storage. During the continuous shelf-conditions (22 ◦C), the flavor-acceptance score of the control fruit gradually decreased to 6.0 after 5 days and to 5.0 after 10 days. After 15 days, the fruit was inedible (flavor score below 5; Figure7e). The flavor scores of the fruits in the sealed packages were significantly (p ≤ 0.05) lower and were inedible (flavor score below 5) already after 5 days. The cucumbers stored in the micro-perforated and macro-perforated packages retained their flavor and had an acceptable flavor score (between 6.75 and 7.0) after 5 days and an edible flavor score (between 6.0 and 6.5) after 10 days, but were judged inedible after 15 days (Figure7e). Foods 2021, 10, 471 8 of 15

between 40 to 70% decay, while the fruit in the micro-perforated packages did not show any decay at all (Figure 7c). In the farm-to-fork supply-chain regime, there was no decay after the marketing simulation. However, after one additional week of refrigerated home storage, the control, non-bagged fruit showed 12.5% decay. After 2 weeks of refrigerated home storage, the level of decay among the control fruits and the fruits in the non-perfo- Foods 2021, 10, 471 8 of 14 rated packages reached 37.5%, while there was a negligible incidence of decay among the fruits in the micro-perforated and macro-perforated packaging (Figure 7d).

FigureFigure 6. Shriveling, 6. Shriveling, pitting, pitting, and wart and wartindices indices of cucumb of cucumbersers stored stored in different in different types typesof packaging. of packaging. MeasurementsMeasurements were weretaken taken during during continuous continuous storage storage under undershelf conditions shelf conditions at 22 °C at (Extended 22 ◦C (Extended shelfshelf life), life),and after and the after simulated the simulated farm-to-fork farm-to-fork supply-chain supply-chain treatment treatment (2 days (2 at days 15 °C at + 152 days◦C + at 2 days 22 °C)at plus22 ◦ C1 )or plus 2 weeks 1 or 2of weeks refrigerated of refrigerated home storage home at storage 4 °C (Supply at 4 ◦ Cchain (Supply + home chain storage). + home Fig- storage). ures Figures(a) and ( ba) andrepresent (b) represent shriveling shriveling indices; Figures indices; ( Figuresc) and (d ()c )represent and (d) representpitting indices, pitting and indices, Fig- and ures e and f represent wart indices after extended shelf life and farm-to-fork supply-chain condi- Figures (e) and (f) represent wart indices after extended shelf life and farm-to-fork supply-chain tions, respectively. Data are means ± SE of 3 replications. Different letters indicate significant dif- conditions, respectively. Data are means ± SE of 3 replications. Different letters indicate significant ferences at p ≤ 0.05. COM—compostable, PP—polypropylene, µP—micro-perforated, MP—macro- ≤ µ perforated,differences NP—non-perforated. at p 0.05. COM—compostable, PP—polypropylene, P—micro-perforated, MP—macro- perforated, NP—non-perforated. 3.7. Fruit Flavor At the end of the farm-to-fork chain simulation (i.e., after 2 weeks of home storage) theThe flavor flavor-acceptance score of the control,score was non-packed 7.5 at harv fruitsest (on had a decreasedscale of 1 to from 9) and the initialdecreased score of during7.5 tostorage. just 5.5. During As observed the continuous under shelf-conditions, shelf-conditions the (22 flavor °C), the scores flavor-acceptance of the fruits in the scorenon-perforated of the control packagesfruit gradually were significantlydecreased to ( p6.0≤ after0.05) 5 lower days andand were to 5.0 inedible after 10 (score days.of 2) Afterdue 15 todays, a strong the fruit off-flavor. was inedible The flavor (flavor scores score of below the cucumbers 5; Figure 7e). in the The micro-perforated flavor scores of and the fruitsmacro-perforated in the sealedpackages packages were were slightly significantly higher (p (between ≤ 0.05) lower 6.0 and and 7.0), were but inedible not significantly (flavor scorediffer below from that5) already of the controlafter 5 days. fruit (FigureThe cucumbers7f). stored in the micro-perforated and

3.8. Visual-Acceptance Score The visual-acceptance score at harvest was 4.5 (i.e., between good and excellent). As can be seen in Figure8a, during continuous storage under shelf conditions (22 ◦C),

the control, non-bagged fruit remained acceptable after 5 days (visual-acceptance score of 3.2). However, after 10 days of shelf life, the visual-acceptance score of the control fruits was signiﬁcantly (p ≤ 0.05) lower and declined far below the threshold value. Fruits in the non-perforated packages were also signiﬁcantly (p ≤ 0.05) lower and unacceptable after 10 days, primarily due to the high incidence of decay. On the other hand, the quality of Foods 2021, 10, 471 9 of 15

macro-perforated packages retained their flavor and had an acceptable flavor score (between 6.75 and 7.0) after 5 days and an edible flavor score (between 6.0 and 6.5) after 10 days, but were judged inedible after 15 days (Figure 7e). Foods 2021, 10, 471 At the end of the farm-to-fork chain simulation (i.e., after 2 weeks of home storage)9 of 14 the flavor score of the control, non-packed fruits had decreased from the initial score of 7.5 to just 5.5. As observed under shelf-conditions, the flavor scores of the fruits in the non-perforatedcucumbers in allpackages of the micro-were significantly and macro-perforated (p ≤ 0.05) lower packages and were remained inedible well (score above of the2) dueacceptance to a strong threshold off-flavor. after The 10 flavor days underscores shelf of the conditions cucumbers (visual-acceptance in the micro-perforated scores ofand 3.1 macro-perforatedto 3.8). Furthermore, packages the appearancewere slightly of thehigher fruits (between in the micro-perforated6.0 and 7.0), but compostablenot signifi- cantlypackaging differ wasfrom acceptable that of the even control after fruit 15 days(Figure of shelf7f). conditions (Figure8a).

Extended shelf life Supply chain + home storage 3 3 a a b ab a 2 ab 2

ab a ColorIndex Colorindex b b a a 1 a 1 a b a b a a a a a a b a a a a a a a a a aa 0 0 T0 5d 10d 15d a 100 50 c a d 90 ab a 80 40 a 70 60 30 b 50 b

40 Decay(%) 20 Decay (%) Decay 30 a 20 10 a 10 b b b b C b b b b b b b 0 0 T0 5d 10d 15d T0 Marketing Marketing + Marketing + 9 9 7d 14d e f a 8 8 a a a a a a a 7 a 7 a a a a a a a a a 6 6 ab ab 5 5 b b Flavor 4 4 Flavor a 3 3 b b ab ab b 2 2 b b 1 1 T0 5d 10d 15d T0 SC SC + 7d HS SC + 14d HS

Control COM-NP COM-µP COM-MP PP-MP FigureFigure 7. 7.ColorColor indices, indices, decay decay levels, levels, and andflavor flavor scores scores of cucumbers of cucumbers kept in kept different in different types of types pack- of aging.packaging. Measurements Measurements were taken were during taken during continuo continuousus storage storage under undershelf conditions shelf conditions at 22 °C at 22(Ex-◦C tended(Extended shelf shelflife) and life) after and afterthe simulated the simulated farm-to-fo farm-to-forkrk supply-chain supply-chain treatment treatment (2 days (2 daysat 15 at°C 15 + ◦2C days+ 2 daysat 22 °C) at 22 plus◦C) 1 plusor 2 weeks 1 or 2 of weeks refrigerated of refrigerated home storage home at storage 4 °C (Supply at 4 ◦C chain (Supply + home chain storage). + home Figuresstorage). (a Figures) and (b ()a )represent and (b) represent color indices; color indices; Figures Figures (c) and (c) ( andd) represent (d) represent decay decay precentages, precentages, andand Figures Figures ((ee)) and and (f )(f) represent represent flavor flavor acceptance acceptance scores scores after extended after extended shelf life andshelf farm-to-fork life and farm-to-forksupply-chain supply-chain conditions, respectively. conditions, Data respectively. are means ± SEData of 3are replications. means ± SE Different of 3 replications. letters indicate Dif- ferentsignificant letters differences indicate significant at p ≤ 0.05. differences COM—compostable, at p ≤ 0.05. COM—compostable, PP—polypropylene, µPP—polypropylene,P—micro-perforated, µP—micro-perforated, MP—macro-perforated, NP—non-perforated. MP—macro-perforated, NP—non-perforated.

3.8. Visual-AcceptanceIn the farm-to-fork Score supply-chain regime, the appearance of all of the fruits remained acceptableThe visual-acceptance after the simulated score distribution-and-marketing. at harvest was 4.5 (i.e., between However, good the and visual-acceptance excellent). As canscores be seen of the in fruits Figure packed 8a, during in micro-perforated continuous storage and macro-perforated under shelf conditions packages (22 were °C), some- the control,what higher non-bagged (between fruit 4.0 remained and 4.25) acceptable than the after scores 5 days of the (visual-acceptance control fruits and score those of of3.2). the However,fruits in non-perforatedafter 10 days of packagesshelf life, (betweenthe visual-acceptance 3.2 and 3.3; score Figure of8 b).the Aftercontrol one fruits week was of significantlyrefrigerated (p home ≤ 0.05) storage, lower theandappearance declined far of below the control the threshold non-packed value. fruits Fruits was in the unaccept- non- perforatedable (visual-acceptance packages were score also ofsignificantly 2.25). In contrast, (p ≤ 0.05) fruits lower in the and non-perforated unacceptable packagesafter 10 were just above the minimum acceptability threshold (visual-acceptance score of 2.6), fruits in macro-perforated packages had moderate scores of 3.2 to 3.5, and fruits in the micro-perforated compostable packages had the highest visual-acceptance score of 4.0 (Figure8b). After 2 weeks of home storage, only the fruits in the perforated packages remained acceptable, while the acceptance scores of the control fruit and of the fruit in the non-perforated packages were signiﬁcantly (p ≤ 0.05) lower and below the acceptability Foods 2021, 10, 471 10 of 15

days, primarily due to the high incidence of decay. On the other hand, the quality of cucumbers in all of the micro- and macro-perforated packages remained well above the acceptance threshold after 10 days under shelf conditions (visual-acceptance scores of 3.1 to 3.8). Furthermore, the appearance of the fruits in the micro-perforated compostable packaging was acceptable even after 15 days of shelf conditions (Figure 8a). In the farm-to-fork supply-chain regime, the appearance of all of the fruits remained acceptable after the simulated distribution-and-marketing. However, the visual-acceptance scores of the fruits packed in micro-perforated and macro-perforated packages were somewhat higher (between 4.0 and 4.25) than the scores of the control fruits and those of the fruits in non-perforated packages (between 3.2 and 3.3; Figure 8b). After one week of refrigerated home storage, the appearance of the control non-packed fruits was unacceptable (visual-acceptance score of 2.25). In contrast, fruits in the non-perforated packages were just above the minimum acceptability threshold (visual-acceptance score of 2.6), fruits in macro-perforated packages had moderate scores of 3.2 to 3.5, and fruits in Foods 2021, 10, 471 the micro-perforated compostable packages had the highest visual-acceptance score of10 4.0 of 14 (Figure 8b). After 2 weeks of home storage, only the fruits in the perforated packages remained acceptable, while the acceptance scores of the control fruit and of the fruit in the non-perforated packages were significantly (p ≤ 0.05) lower and below the acceptability limit (Figure8b). It is worth noting that the visual-acceptance scores of the cucumbers limit (Figure 8b). It is worth noting that the visual-acceptance scores of the cucumbers stored in micro- and macro-perforated compostable packages were somewhat higher (3.25) stored in micro- and macro-perforated compostable packages were somewhat higher than those of the cucumbers stored in the macro-perforated polypropylene bags (2.75), but (3.25) than those of the cucumbers stored in the macro-perforated polypropylene bags that difference was not statistically signiﬁcant. (2.75), but that difference was not statistically significant.

E x te n d ed s h e lf life Supply chain + home storage 5 a 5 b a ab a ab ab ab a 4 a 4 ab b b ab b b a b ab a 3 3 a a b ab b Acceptance score Acceptance Acceptance score Acceptance 2 c 2 b b c b b b 1 1 T0 5d 10d 15d T0 SC SC + 7d HS SC + 14d HS

Control COM-NP COM-µP COM-MP PP-MP

Figure 8. Acceptance scores of cucumbers kept in the different types of packaging. Measurements Figurewere taken8. Acceptance during continuous scores of cucumbers storage under kept shelf in the conditions different attypes 22 ◦ Cof (Extendedpackaging. shelf Measurements life) and after werethe simulatedtaken during farm-to-fork continuous supply-chain storage under treatment shelf conditions (2 days at 15 at◦ 22C +°C 2 days(Extended at 22 ◦ C)shelf plus life) 1 or and 2 weeks afterof refrigerated the simulated home farm-to-fork storage at supply-chain 4 ◦C (Supply treatmen chain +thome (2 days storage). at 15 °CFigures + 2 days (a at) and 22 °C) (b) plusrepresent 1 or 2 weeks of refrigerated home storage at 4 °C (Supply chain + home storage). Figures (a) and (b) overall acceptance scores after extended shelf life and farm-to-fork supply-chain conditions, respec- represent overall acceptance scores after extended shelf life and farm-to-fork supply-chain condi- tively. Data are means ± SE of 3 replications. The red dashed line indicates the minimum acceptance tions, respectively. Data are means ± SE of 3 replications. The red dashed line indicates the mini- mumthreshold acceptance of 2.5. threshold Different of letters 2.5. Different indicate letters significant indicate differences significant at pdifferences≤ 0.05. COM—compostable, at p ≤ 0.05. COM—compostable,PP—polypropylene, PP—polypropylene,µP—micro-perforated, µP—mic MP—macro-perforated,ro-perforated, MP—macro-perforated, NP—non-perforated. NP— non-perforated. 4. Discussion 4. DiscussionThe main goals of the current study were to evaluate whether compostable packages may replace the conventional plastic films currently used to preserve the freshness The main goals of the current study were to evaluate whether compostable packages and postharvest quality of cucumber fruits, and to get an idea of beneficial compostable may replace the conventional plastic films currently used to preserve the freshness and packaging design for cucumbers. Cucumbers are highly perishable commodities prone postharvest quality of cucumber fruits, and to get an idea of beneficial compostable pack- to postharvest deterioration, caused by desiccation, senescence, and microbial spoilage. aging design for cucumbers. Cucumbers are highly perishable commodities prone to post- Efficient packaging should provide optimal storage microenvironment reducing moisture harvest deterioration, caused by desiccation, senescence, and microbial spoilage. Efficient loss by enhanced air humidity, and inhibiting pathogen development and ethylene-induced packaging should provide optimal storage microenvironment reducing moisture loss by senescence by elevated carbon dioxide and reduced oxygen levels. On the other hand, the enhanced air humidity, and inhibiting pathogen development and ethylene-induced se- extreme humidity and atmosphere composition changes should be avoided in order to nescence by elevated carbon dioxide and reduced oxygen levels. On the other hand, the prevent undesirable phenomena such as water condensation encouraging disease devel- extremeopment, humidity carbon dioxideand atmosphere injury and composition hypoxic fermentation changes should causing be off-flavorsavoided in andorder tissue to damage. For cucumbers, exposure to carbon dioxide levels above 5 [22,23] or 10% [24] results in injury manifested as enhanced decay susceptibility and yellowing. The low-oxygen tolerance of cucumbers is 3% [24]. The creation of modified atmosphere and humidity within fruit and vegetable packaging depends on the interaction between produce respiration and transpiration processes, and barrier properties of the packaging material towards gases and water vapor [25]. As compared to regular petroleum-based polypropylene film of the same thickness, the compostable packaging material examined in this study had five-fold higher water vapor transmission rate, but 2.5-fold lower oxygen permeability. Such trend is typical for biobased compostable films [26,27]. The low oxygen transmission rate of the compostable film increases the risk of hypoxic fermentation in respiring fresh produce like cucumbers. Such risk is especially high at super-optimal shelf-life temperature when enhanced res- piratory consumption of oxygen is not balanced by adequate gas exchange through the packaging material. Micro-perforation is an efficient way to prevent the hypoxia by matching the package oxygen permeability with produce requirements [28]. Perforations have great effect on oxygen and carbon dioxide transfer through packaging material, but much smaller influence on water vapor transmission that partially passes through polymer matrix [29]. Foods 2021, 10, 471 11 of 14

This disparity allows the approach of modified atmosphere and modified humidity (MA– MH) packaging when desirable atmosphere composition is reached due to appropriate micro-perforation level, while in-package humidity is adjusted and water condensation is prevented by choosing a suitable plastic basis. The MA–MH approach was realized commercially in a series of micro-perforated packages based on polyamide blends having higher WVTR as compared to regular polyolefins [30].). The enhanced-WVTR compostable film demonstrated similar MA–MH potential, in addition to its sustainability advantage. Indeed, no water condensation was observed in the micro-perforated compostable packages, in contrast to the commercial polypropylene packs where profound accumulation of condensed water eventually resulted in sharp decay increase (Figure7c). On the other hand, storage in micro-perforated compostable bags significantly reduced the weight loss of cucumbers as compared to the open containers, and prevented their shriveling (Figure5a,b and Figure6a,b). Future improvement of the compostable film formulation might allow modulating the WVTR value in order to reach even lower produce weight loss without compromising the condensation control. Mathematical modeling can be helpful for determining an optimal package micro-perforation level (28). However, such optimization has been out of the scope of the present study. The existing models typically based on conventional petroleum-based plastics need adjustment in order to allow reliable description of packaging systems involving relatively hydrophilic biodegradable materials. For example, in contrast to regular polyolefins the barrier properties of such films may be strongly affected by air humidity (Hong and Krochta, 2006) [31]. Moreover, in this work we have demonstrated for the first time the effect of biological factors such as mold development, on the barrier properties of biodegradable package (see below). Therefore, theoretical description of biodegradable packaging systems needs a special in-depth analysis that may be a subject of a separate study. The results of this study clearly indicate that compostable packaging may preserve cucumber quality under various storage conditions: continuous shelf life at 22 ◦C and a simulated farm-to-fork supply chain, including distribution, marketing, and refrigerated home storage. The appropriate compostable packaging controlled fruit weight loss, shriveling, peel disorders, yellowing, decay, and flavor deterioration. However, the ability of the compostable packaging to preserve cucumber quality greatly depended on the perforation rate. According to our results, the micro-perforated compostable packaging resulting in the creation of a modified atmosphere containing approximately 15–17% O2 and 2–5% CO2 was preferable for preserving cucumber quality, as compared to both non-perforated and macro-perforated packaging (Figure4). This finding is in agreement with the previous observation of Manjunatha and Anurag [21], who reported that modified atmospheres containing 12–17% O2 and 5–10% CO2 have a positive effect on cucumber preservation. On the other hand, the macro-perforated packages had internal atmospheres similar to regular air and were somewhat less effective in reducing pitting, warts, yellowing, and decay development, as compared with the micro-perforated packages (Figures6 and7). We found that storage of cucumbers in non-perforated compostable packages resulted in the development of hypoxic conditions with just ~1.5% O2 (Figure4), which is below the tolerance level of cucumbers [19,24]. Accordingly, using sealed compostable packages enhanced decay development and harmed fruit flavor. Therefore, non-perforated packages are not recommended for the storage and marketing of cucumbers. The sharp increase in the level of oxygen in the atmosphere within the non-perforated packages during the second half of the storage period (Figure4a,b) requires further examination. During the trials, we observed the effect of spoilage microorganisms on the integrity of the compostable films (Figure9). Once this air influx into the non-perforated packages coincided with the onset of profound decay on hypoxia-damaged cucumbers, it was probably associated with partial microbial degradation of the packaging. However, such re-exposure to oxygen did not reverse the hypoxic damage to plant tissues and might have even aggravated that damage [32]. Foods 2021, 10, 471 12 of 15

CO2 was preferable for preserving cucumber quality, as compared to both non-perforated and macro-perforated packaging (Figure 4). This finding is in agreement with the previous observation of Manjunatha and Anurag [21], who reported that modified atmospheres containing 12–17% O2 and 5–10% CO2 have a positive effect on cucumber preservation. On the other hand, the macro-perforated packages had internal atmospheres similar to regular air and were somewhat less effective in reducing pitting, warts, yellowing, and decay development, as compared with the micro-perforated packages (Figures 6 and 7). We found that storage of cucumbers in non-perforated compostable packages resulted in the development of hypoxic conditions with just ~1.5% O2 (Figure 4), which is below the tolerance level of cucumbers [19,24]. Accordingly, using sealed compostable packages enhanced decay development and harmed fruit flavor. Therefore, non-perforated packages are not recommended for the storage and marketing of cucumbers. The sharp increase in the level of oxygen in the atmosphere within the non-perforated packages during the second half of the storage period (Figure 4a,b) requires further examination. During the trials, we observed the effect of spoilage microorganisms on the integrity of the compostable films (Figure 9). Once this air influx into the non-perforated packages coincided with the onset of profound decay on hypoxia-damaged cucumbers, it was prob- Foods 2021, 10, 471 ably associated with partial microbial degradation of the packaging. However, such12 of re- 14 exposure to oxygen did not reverse the hypoxic damage to plant tissues and might have even aggravated that damage [32].

FigureFigure 9.9. EffectsEffects ofof spolagespolage organisimsorganisims onon thethe integrityintegrity ofof compostablecompostablepackages. packages.

WeWe further further compared compared the the effects effects of of the the compostable compostable packaging packaging with with those those of commer- of com- cialmercial macro-perforated macro-perforated polypropylene polypropylene plastic plastic packaging packaging and and found found that that the the compostable composta- packagingble packaging reduced reduced cucumber cucumber weight weight loss loss almost almost as as well well as as the the polypropylene polypropylene plastic plastic packaging,packaging, butbut withoutwithout thethe creationcreation ofof condensationcondensation (Figure(Figure5 ).5). Low Low condensation condensation rates rates constituteconstitute anan importantimportant advantageadvantage ofof thethe compostablecompostable packagespackages overover regularregular plasticplastic films,films, sincesince thethe accumulationaccumulation ofof freefree waterwater withinwithin thethe packagespackages maymay enhanceenhance microbialmicrobial spoilagespoilage andand harmharm foodfood safetysafety [[33].33]. TheThe low-condensationlow-condensation characteristicscharacteristics ofof thethe compostablecompostable pack-pack- agesages alsoalso eliminateeliminate thethe needneed toto addadd absorbingabsorbing pads,pads, whichwhich makemake thethe packagingpackaging processprocess moremore complexcomplex andand expensiveexpensive [[34].34]. Nonetheless,Nonetheless, itit shouldshould bebe mentionedmentioned thatthat wewe herebyhereby ® examinedexamined aa specificspecific typetype ofof aa compostablecompostable packagingpackaging materialmaterial manufacturedmanufactured byby TIPATIPA® Corp.,Corp., whilewhile other types types of of compostable compostable mate materialsrials may may have have different different water water vapor vapor perme- per- meability’sability's and and consequent consequent condensation condensation rates rates [35]. [35 Furthermore,]. Furthermore, various various additives additives that thatmay maybe applied be applied to the to compostable the compostable films, films, such such as soybean as soybean oil, oil,may may further further influence influence water water re- resistancesistance properties properties [36]. [36]. OtherOther advantages of of the the micr micro-perforatedo-perforated compostable compostable pa packagesckages over over the themacro-per- macro- perforatedforated polypropylene polypropylene packages packages are the are observed the observed reductions reductions in warts, in warts,decay, decay,and yellow- and yellowinging (Figures (Figure 6e,f and6e,f 7a,c). and FigureNonetheless,7a,c). Nonetheless, these effects theseare prob effectsably arerelated probably to the related creation to the creation of favorable modified atmospheres within the micro-perforated packages rather than any unique properties of the compostable film.

5. Conclusions Overall, our results indicate that, compared to non-packed produce, the micro- perforated compostable packaging extended the shelf-life of cucumbers kept at 22 ◦C by at least 5 days and increased cucumber shelf-life by more than 7 days in a simulated supply-chain treatment that was followed by refrigerated home storage (Figure8). These results regarding the extension of the postharvest storage life of cucumbers by compostable packages are in agreement with previous reports demonstrating the advantages of MAP for extending the storage life of cucumbers [20,21,37]. Nevertheless, here, we have demonstrated for the ﬁrst time that compostable packaging material may provide an environmentally friendly alternative to the commonly used plastic retail packaging [38].

Author Contributions: Conceptualization, R.P. and V.R.; Data curation, A.O.; Investigation, A.O., R.P., and V.R.; Methodology, R.P. and V.R.; Project administration, R.P.; Resources, R.P.; Validation, V.R.; Visualization, A.O.; Writing—original draft, R.P.; Writing—review and editing, R.P. and V.R. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. Data Availability Statement: Not applicable. Foods 2021, 10, 471 13 of 14

Acknowledgments: We thank TIPA® Corp. for providing the compostable packaging used for these trials. Conﬂicts of Interest: The authors declare no conﬂict of interest.

References 1. Kader, A.A. Postharvest biology and technology: An overview. In Postharvest Technology of Horticultural Crops; Kader, A.A., Ed.; Regents of the University of California, Division of Agricultural and Natural Resources: Oakland, CA, USA, 2002; pp. 39–47. 2. FAO (Food and Agriculture Organization of the United Nations). Global Food Losses and Food Waste: Extent, Causes and Prevention; Study Conducted for the International Congress SAVE FOOD! At Interpack, Düsseldorf, Germany; FAO: Rome, Italy, 2011. Available online: http://www.fao.org/docrep/014/mb060e/mb060e00.Pdf (accessed on 1 February 2021). 3. Lipinski, B.; Hanson, C.; Lomax, J.; Kitinoja, L.; Waite, R.; Searchinger, T. Reducing food loss and waste. In Working Paper, In-stallment 2 of Creating a Sustainable Food Future; World Resources Institute: Washington, DC, USA, 2013. Available online: https://pdf.wri.org/reducing_food_loss_and_waste.pdf (accessed on 1 February 2021). 4. NRDC. Wasted: How America is Losing Up to 40 Percent of Its Food from Farm to Fork to Landfill. NRDC Issue PAPER, R: 17-05-A (2nd edition of NRDC’s original paper from 2012). 2017. Available online: https://www.nrdc.org/sites/default/files/ wasted-2017-report.pdf (accessed on 1 February 2021). 5. Buzby, J.C.; Wells, H.F.; Hyman, J. The Estimated Amount, Value, and Calories of Postharvest Food Losses at the Retail and Consumer Levels in the United States, EIB-121, U.S. Department of Agriculture, Economic Research Service. 2014. Available online: https://www.ers.usda.gov/webdocs/publications/43833/43680_eib121.pdf (accessed on 1 February 2021). 6. Opara, U.L. A review on the role of packaging in securing food system: Adding value to food products and reducing losses and waste. Afric. J. Agric. Res. 2013, 8, 2621–2630. 7. Verghese, K.; Lewis, H.; Lockrey, S.; Williams, H. Packaging’s Role in Minimizing Food Loss and Waste Across the Supply Chain. Packag. Technol. Sci. 2015, 28, 603–620. [CrossRef] 8. Wikström, F.; Verghese, K.; Auras, R.; Olsson, A.; Williams, H.; Wever, R.; Grönman, K.; Pettersen, M.K.; Møller, H.; Soukka, R. Packaging Strategies That Save Food: A Research Agenda for 2030. J. Ind. Ecol. 2018, 23, 532–540. [CrossRef] 9. AMERIPEN. Quantifying the Value of Packaging as a Strategy to Prevent Food Waste in America. 2018. Available online: https://www.ameripen.org/page/foodwastereport (accessed on 1 February 2021). 10. Kader, A.A.; Zagory, D.; Kerbel, E.L.; Wang, C.Y. Modified atmosphere packaging of fruits and vegetables. Crit. Rev. Food Sci. Nutr. 1989, 28, 1–30. [CrossRef] 11. Rai, D.R.; Oberoi, H.S.; Baboo, B. Modified atmosphere packaging and its effect on quality and shelf life of fruits and vegeta-bles: An overview. J. Food Sci. Tech. 2002, 39, 199–207. 12. Kader, A.A. Modified atmosphere during transport and storage. In Postharvest Technology of Horticultural Crops; Kader, A.A., Ed.; Regents of the University of California, Division of Agricultural and Natural Resources: Oakland, CA, USA, 2002; pp. 135–144. 13. Saltveit, M. A summary of CA requirements and recommendations for vegetables. Acta Hortic. 2003, 600, 723–727. [CrossRef] 14. Xanthos, D.; Walker, T.R. International policies to reduce plastic marine pollution from single-use plastics (plastic bags and microbeads): A review. Mar. Pollut. Bull. 2017, 118, 17–26. [CrossRef][PubMed] 15. Ellen MacArthur Foundation & UNEP. The New Plastics Economy Global Commitment Progress Report. Available online: https://www.ellenmacarthurfoundation.org/assets/downloads/Global-Commitment-2019-Progress-Report.pdf (accessed on 1 February 2021). 16. Khalil, H.P.S.A.; Banerjee, A.; Saurabh, C.K.; Tye, Y.Y.; Suriani, A.B.; Mohamed, A.; Karim, A.A.; Rizal, S.; Paridah, M.T. Biodegradable Films for Fruits and Vegetables Packaging Application: Preparation and Properties. Food Eng. Rev. 2018, 10, 139–153. [CrossRef] 17. Wróblewska-Krepsztul, J.; Rydzkowski, T.; Borowski, G.; Szczypiński,M.; Klepka, T.; Thakur, V.K. Recent progress in biodegradable polymers and nanocomposite-based packaging materials for sustainable environment. Inter. J. Poly. Anal. Char. 2018, 23, 383–395. [CrossRef] 18. Jamróz, E.; Kopel, P.; Tkaczewska, J.; Dordevic, D.; Jancikova, S.; Kulawik, P.; Milosavljevic, V.; Dolezelikova, K.; Smerkova, K.; Svec, P.; et al. Nanocomposite Furcellaran Films—the Influence of Nanofillers on Functional Properties of Furcellaran Films and Effect on Linseed Oil Preservation. Polymers 2019, 11, 2046. [CrossRef][PubMed] 19. Suslow, T.V.; Cantwell, M. Cucumbers: Recommendations for Maintaining Postharvest Quality. 2002. Available online: http://ucanr.edu/sites/Postharvest_Technology_Center_/Commodity_Resources/Fact_Sheets/Datastores/Vegetables_ English/?uid=19&ds=799 (accessed on 1 February 2021). 20. Kahramano˘glu,I.; Usanmaz, S. Improving Postharvest Storage Quality of Cucumber Fruit by Modified Atmosphere Packaging and Biomaterials. HortScience 2019, 54, 2005–2014. [CrossRef] 21. Manjunatha, M.; Anurag, R.K. Effect of modified atmosphere packaging and storage conditions on quality characteristics of cucumber. J. Food Sci. Technol. 2012, 51, 3470–3475. [CrossRef][PubMed] 22. Watkins, B.C. Responses of horticultural commodities to high carbon dioxide as related to modified atmosphere packaging. HortTechnology 2000, 10, 501–506. [CrossRef] Foods 2021, 10, 471 14 of 14

23. Mir, N.; Beaudry, R. Modified atmosphere packaging. In The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Stocks. Agriculture Handbook 66; Gross, K.C., Wang, C.Y., Saltveit, M., Eds.; USDA, Agricultural Research Service: Washington, DC, USA, 2016; pp. 42–53. 24. Saltveit, M.E. Biological basis for CA and MA. In Controlled and Modified Atmospheres for Fresh and Fresh-Cut Produce; Elsevier BV: Amsterdam, The Netherlands, 2020; pp. 3–22. 25. Fonseca, S.C.; Oliveira, F.A.; Brecht, J.K. Modelling respiration rate of fresh fruits and vegetables for modified atmosphere packages: A review. J. Food Eng. 2002, 52, 99–119. [CrossRef] 26. Flodberg, G.; Helland, I.; Thomsson, L.; Fredriksen, S.B. Barrier properties of polypropylene carbonate and poly(lactic acid) cast films. Eur. Polym. J. 2015, 63, 217–226. [CrossRef] 27. Wang, J.; Gardner, D.J.; Stark, N.M.; Bousfield, D.W.; Tajvidi, M.; Cai, Z. Moisture and Oxygen Barrier Properties of Cellulose Nanomaterial-Based Films. ACS Sustain. Chem. Eng. 2018, 6, 49–70. [CrossRef] 28. González, J.; Ferrer, A.; Oria, R.; Salvador, M.L. Determination of O2 and CO2 transmission rates through microperforated films for modified atmosphere packaging of fresh fruits and vegetables. J. Food Eng. 2008, 86, 194–201. [CrossRef] 29. Rodov, V.; Aharoni, N.; Cohen, S.; Ben-Yehoshua, S. Modified Humidity Packaging of Fresh Produce. Hortic. Rev. 2010, 37, 281–329. [CrossRef] 30. Aharoni, N.; Rodov, V.; Fallik, E.; Afek, U.; Chalupowicz, D.; Aharon, Z.; Maurer, D.; Orenstein, J. Modified Atmosphere Packaging for Vegetable Crops Using High-Water-Vapor-Permeable Films; CRC Press: Boca Raton, FL, USA, 2007; pp. 73–112. 31. Hong, S.-I.; Krochta, J.M. Oxygen barrier performance of whey-protein-coated plastic films as affected by temperature, relative humidity, base film and protein type. J. Food Eng. 2006, 77, 739–745. [CrossRef] 32. Das, A.; Uchimiya, H. Oxygen stress and adaptation of a semi-aquatic plant: Rice (Oryza sativa). J. Plant Res. 2002, 115, 315–320. [CrossRef] 33. Bovi, G.G.; Caleb, O.J.; Rauh, C.; Mahajan, P.V. Condensation regulation of packaged strawberries under fluctuating storage temperature. Packag. Technol. Sci. 2019, 32, 545–554. [CrossRef] 34. Bovi, G.G.; Caleb, O.J.; Klaus, E.; Tintchev, F.; Rauh, C.; Mahajan, P.V. Moisture absorption kinetics of FruitPad for packag-ing of fresh strawberry. J. Food Engin. 2018, 223, 248–254. [CrossRef] 35. Briassoulis, D.; Giannoulis, A. Evaluation of the functionality of bio-based food packaging films. Polym. Test. 2018, 69, 39–51. [CrossRef] 36. Przybytek, A.; Sienkiewicz, M.; Kucińska-Lipka,J.; Janik, H. Preparation and characterization of biodegradable and com-postable PLA/TPS/ESO compositions. Indus. Crops Prod. 2018, 122, 375–383. [CrossRef] 37. Dhall, R.K.; Sharma, S.R.; Mahajan, B.V.C. Effect of shrink wrap packaging for maintaining quality of cucumber during storage. J. Food Sci. Technol. 2011, 49, 495–499. [CrossRef] 38. Guillard, V.; Gaucel, S.; Fornaciari, C.; Angellier-Coussy, H.; Buche, P.; Gontard, N. The Next Generation of Sustainable Food Packaging to Preserve Our Environment in a Circular Economy Context. Front. Nutr. 2018, 5, 121. [CrossRef][PubMed]