Exogenous Polyamines and Gibberellic Acid Effects on Peach (Prunus Persica L.) Storability Improvement D

JFS: Food Chemistry and Toxicology

Exogenous Polyamines and Gibberellic Acid Effects on Peach (Prunus persica L.) Storability Improvement D. MARTÍNEZ-ROMERO, D. VALERO, M. SERRANO, F. BURLÓ, A. CARBONELL, L. BURGOS, AND F. R IQUELME Food Chemistry and Toxicology ABSTRACT: Peaches (Prunus persica L., cv. Babygold 6) harvested at the stage of commercial ripening were pressure- -1 infiltrated with putrescine (1 mM) or GA3 (100 mg L ) and then stored at 2 °C for 14 d. Both treatments increased fruit firmness, putrescine-treated peaches being significantly firmer than control ones. Treatments were also effective in reducing the susceptibility of the fruit to be damaged by mechanically compression with lower volume and surface of the damage zone. Ethylene emission and the respiration rate were reduced in treated fruits, which reflects a delay of the ripening process. The effects of the mechanical stress could be related to increased spermidine levels, rather than ethylene emission and respiration rate during storage.

Key Words: CO2, ethylene, gibberellic acid, mechanical damage, polyamines

Introduction prolonged fruit storage, physiological processes that are usually TRESS IS USUALLY CATEGORIZED BY BIOLOGICAL OR ENVIRON- accompanied by decreases in plant polyamines. Thus, Smental factors, such as chilling injury and mechanical dam- polyamines infiltration in lemons, harvested at color break, de- age, that induces fruit injury and quality degradation in fruits layed the color change to yellow, reduced the weight loss during (Serrano and others 1996; Valero and others 1998c). Mechanical storage, and increased fruit firmness through the maintenance damage is initiated by the breakage of cell membranes and of higher endogenous putrescine and spermidine levels than browning caused by the action of cytosolic enzymes. Other phys- those found in controls (Valero and others 1998a). The mecha- iological changes are an increased respiration rate and wounding nism by which polyamines increase fruit firmness is still unclear, ethylene emission, which lead to an accelerated ripening process but changes in polygalacturonic acids seem to be involved, spe- (Miller 1992). cially by electrostatic bounds between the carboxylic groups and Fruit ripening is a late stage of growth prior to the senescence polyamines (Leiting and Wicker 1997). process. Peach fruit has been categorized as a climacteric fruit, Polyamines have been considered as antisenescent agents since the fruit exhibits a peak in respiration parallel to the cli- with changes in their levels being reported as a protective mech- macteric ethylene production (Amorós and others 1989). The anism. However, in different species reported different sharp increase in climacteric ethylene emission is considered as a polyamines are involved (Kakkar and Rai 1993), and there seem trigger that controls changes in texture, color, flavor, and aromas to be species specific relationship. In most of these papers, an ac- (Leliévre and others 1997). These parameters may not be inde- cumulation of polyamines (putrescine, spermidine, and/or sper- pendent of each other and should be studied together to dem- mine) has been found in response to several plant and fruit onstrate the fruit quality. In general, as fruits ripen and soften stresses, being chilling injury the most studied stress (Serrano they become more susceptible to mechanical damage (Miller and others 1996). 1992). Peach has been considered as one of the most susceptible Gibberellins (alone or combined) are used with different pur- fruits to bruise caused by impact, vibration, and compression poses. Thus, preharvest application of gibberellins improved ap- forces, from a packaging, distribution, and the production losses ple quality and tree productivity (Looney and others 1992), and point of views (Vergano and others 1991). This susceptibility to exogenous GA3 improved the firmness in ‘Loadel’ cling peach suffer mechanical damage has led to a decline in the consump- (Southwick and others 1995). Postharvest GA3 delayed mango tion of fresh market peaches in recent years (Vergano and others and strawberry ripening retarding chlorophyll degradation in the 1995). Several researches have shown that bruising is linearly re- peel (Khader 1992). lated to impact energy, with a direct relationship between impact The objective of this paper was to study the effects of the ex- intensity and the resulting bruise response, defined as bruise di- ogenous applications of putrescine (at 1 mM) and GA3 (at 100 mg mension (Maness and others 1992). L-1) on the levels of ethylene emission, respiration rate, endoge- Peach fruits are highly perishable and attain an acceptance nous polyamines, and firmness, in order to improve the storabili- flavor only after they are softer than desired for handling. Fruits ty and shelf life of peaches stored at 2 °C. Also, the effects of the are commonly harvested in immature stage to reduce bruising 2 treatments on modifying the peach susceptibility to be dam- and to extend their shelf life. However, variations of color and aged after a compression force of 25 Newton (N) were investigat- firmness have been reported among different peach varieties ed. (Robertson and others 1993), being this parameter the best sin- gle indicator of fruit ripening. Results It is known that polyamines play an important role in fruit de-

velopment. Recently, the polyamine metabolism and its regula- Effect of putrescine and GA3 treatments on peach tion has been reviewed (Tiburcio and others 1997; Valero and firmness others 1999). Exogenous polyamines delayed senescence and Initial whole fruit firmness, determined as deformation slope,

288 JOURNAL OF FOOD SCIENCE—Vol. 65, No. 2, 2000 © 2000 Institute of Food Technologists Table 1 – Effect of the treatments on whole fruit and flesh firmness in peaches stored at 2 °C. Whole fruit firmness (N) Flesh fruit Firmness

Days Putrescine GA3 Control Putrescine GA3 Control 0 17.08 ± 0.67a 17.08 ± 0.67a 17.08 ± 0.67a 6.95 ± 0.48a 6.95 ± 0.48a 6.95 ± 0.48a 1 15.31 ± 1.10a 13.43 ± 1.08a 12.74 ± 1.72a 8.62 ± 0.51a 7.22 ± 0.53ab 6.01 ± 0.48b 2 13.35 ± 0.55a 13.12 ± 0.87a 11.88 ± 0.27a 7.82 ± 0.88a 6.03 ± 0.52b 4.79 ± 0.60b 4 11.06 ± 0.74a 10.56 ± 0.12ab 9.18 ± 0.54b 6.33 ± 0.45a 5.03 ± 0.43b 4.14 ± 0.54b 10 8.94 ± 0.85a 7.80 ± 0.47ab 6.58 ± 0.34b 6.63 ± 0.51a 4.20 ± 0.45b 4.49 ± 0.14b 14 6.24 ± 0.27a 6.73 ± 0.48ab 4.90 ± 0.61b 5.63 ± 0.31a 3.98 ± 0.36b 4.54 ± 0.34b For each firmness parameter, values with the same letter in rows are not significantly different at P < 0.05.

was 17.08 ± 0.67 N (Table 1). For all treatments, fruit firmness di- Table 2 –Damaged volume, and surface, and fruit deformation percentage under a force of 25 N applied following different treatments minished significantly during storage. However, peaches that in peach were infiltrated with putrescine showed significantly higher firm- th Putrescine GA3 Control ness levels than control fruits from the 4 d of storage. GA3-treated peaches did not show significant differences when compared Volume 229.90 ± 36.95a 299.23 ± 36.98a 378.36 ± 48.37b a a b with putrescine-treated or control fruits. Surface 73.07 ± 9.54 90.97 ± 9.45 111.56 ± 11.31 Deformation 5.04 ± 0.11a 5.29 ± 0.13ab 5.56 ± 0.18b Initial flesh fruit firmness was 6.95 ± 0.48 N (Table 1). In GA3- Values with the same letter in rows are not significantly different at P < 0.05. treated and control fruits, a continuous decrease of flesh fruit firmness was observed along the experiment, with no significant differences between them. However, peaches that were putrescine-infiltrated showed a significant increase in flesh fruit Food Chemistry and Toxicology firmness (from 6.95 ± 0.48 N to 8.62 ± 0.51 N) 24 h after the treat- fruits, respectively). From this time on, the CO2 content signifi- ment. From this time, flesh firmness decreased during the next 4 cantly increased in both treated and control peaches. At the 10th d of storage and remained practically stable until the end of the d, control fruits showed a significant peak in CO2 rate (54.94 ± experiment, being these values significantly higher than those 2.50 mg kg-1 h-1), that coincided with the climacteric ethylene found in GA3-treated and control peaches. peak. In putrescine- and GA3-treated fruits, the maximum con- -1 - tent of CO2 was delayed 4 d, with values of 53.09 ± 1.85 mg kg h Bruising determination 1 and 45.30 ± 2.11 mg kg-1 h-1, respectively. Bruising occurrence as a consequence of the compression In relation to peaches affected by mechanical damage, the force of 25 N was different depending on the treatment applied ethylene production (Fig. 2a) during the 1st 10 d of storage did for both volume and surface dimensions (Table 2). Considering not show significant differences among the fruits. The ethylene the volume and the surface of control peaches as 100%, the pu- emission decreased significantly 24 h after the treatments were trescine treatment significantly reduced by 40% the bruising vol- performed, and slightly increased after 10 d of storage. At 14th d, ume and by 35% the bruising surface, while the GA3 treatment the ethylene production was significantly higher in putrescine- decreased the bruising volume and the bruising surface by 21% treated peaches (39.53 ± 1.64 nL g-1 h-1) than those found in both -1 -1 and 19%, respectively. controls (17.62 ± 0.96 nL g h ) and GA3-treated fruits (21.68 ± Whole fruit deformation as a consequence of the compression 2.17 nL g-1 h-1), being this level the highest of the experiment. force of 25 N was lower in putrescine-treated and GA3-treated In peaches submitted to the external force of 25 N (Fig. 2b), st peaches as compared with controls, but differences were only their initial CO2 levels decreased during the 1 2 d of storage for significant between fruits infiltrated with putrescine and control all fruits, showing control peaches the lowest value (19.23 ± 1.11 -1 -1 th ones (Table 2). Both putrescine and GA3 treatments reduced the mg kg h ). From the 4 d, the evolution of CO2 was the same whole fruit deformation by 10% and by 5%, respectively, in rela- than that found for ethylene emission. GA3-treated and control tion to control fruits. fruits maintained constant their levels until the end of storage, while putrescine-treated peaches increased significantly the CO2 th Ethylene and CO2 productions in nondamaged and content at the 14 d, reaching the largest value (63.19 ± 3.05 mg damaged peaches kg-1 h-1). Ethylene production in recently harvested fruits was 23.86 ± 2.17 nL g-1 h-1. This level decreased significantly for all fruits at 1st Polyamine levels day due to the low storage temperature. From this day, control Free polyamines were analyzed in peach, but only putrescine fruits produced significantly higher levels of ethylene than pu- and spermidine were quantified since no levels of spermine were trescine-treated peaches until the 10th d, in which the climacteric detected in both nondamaged and damaged fruits during the peak was achieved for control peaches (32.52 ± 2.55 nL g-1 h-1) experiment. In recently harvested peaches, the levels of endoge- -1 -1 -1 and GA3-treated fruits (23.86 ± 2.17 nL g h ) (Fig. 1a). In pu- nous putrescine were 13.39 ± 0.82 nmol g . For both treated and trescine-treated peaches, the climacteric peak (31.82 ± 1.40 nL g-1 control fruits, concentrations of putrescine increased significant- h-1) was delayed 4 d. No differences were found between fruits ly during the 1st 10 d of storage, at which the maximum was -1 infiltrated with GA3 and control peaches during storage, with the achieved in GA3-treated (41.73 ± 1.94 nmol g ) and control th -1 exception of the 14 d, although the ethylene emission in GA3- peaches (31.44 ± 1.67 nmol g ) (Fig. 3a). In control fruits, the pu- treated fruit were lower. trescine content fell significantly at 14th d of storage (27.38 ± 0.77 -1 -1 -1 Initial levels of CO2 rate was 50.80 ± 3.99 mg kg h (Fig. 1b). nmol g ), while putrescine-treated peaches reached their maxi- This value in recently harvested fruits significantly decreased mum (37.31 ± 2.03 nmol g-1) at the end of the experiment. until the 4th d of storage for all peaches, reaching the lowest lev- Levels of spermidine at day 0 were 46.38 ± 3.85 nmol g-1. Dur- els (28.77 ± 2.44 mg kg-1 h-1, 31.40 ± 2.53 mg kg-1 h-1, and 30.74 ± ing the 1st 4 d of storage (Fig. 3b), both putrescine-treated and -1 -1 2.87 mg kg h , for putrescine-treated, GA3-treated, and control control peaches showed an identical spermidine concentration.

Vol. 65, No. 2, 2000—JOURNAL OF FOOD SCIENCE 289 - TEMPERA

LOW

, respectively) compared , respectively) STORED -1

BE 4 d of storage (235.11 ± 18.18 4 d of storage

st (n), control (s), and then damaged -1 TO

(b) production in peaches treated with 2 Discussion NEED

100 mg L 3 ). From this time and until the end of the ex- time and until the end ). From this -1 FRUITS

-treated, in which significantly lower levels were found which significantly -treated, in and 194.70 ± 18.94 nmol g and 194.70 3 -1 tures to inhibit the ethylene biosynthesis and, subsequent- tures to inhibit the ethylene LIMACTERIC (40.25 ± 3.18 nmol g (40.25 ± 3.18 lower levels than those found in the controls. In these and in pu- In these and controls. in the those found levels than lower sper- accumulate to a clear tendency peaches, trescine-treated 1 shown during the midine was nmol g ly, the initiation of changes in color, aroma, texture, flavor, and flavor, texture, aroma, in color, the initiation of changes ly, physiological attributes (Leliévre and oth- other biochemical and during the However, shelf life. a prolonged ers 1997), leading to lose firmness and get soft, with an accelera- storage period, fruits and others 1997), exhibiting tion of the ripening (Valero process C periment, treated peaches showed identical spermidine con- identical spermidine treated peaches showed periment, found in con- lower than those were significantly tents and they trol fruits. with GA putrescine 1mM (l), GA with a compression force of 25 N during storage at 2 °C. Data are the mean ± SE. Fig. 2—Ethylene (a) and CO - 3 in pu- -1 d. th d (25.81 ± 1.26 nmol ± 1.26 d (25.81 th in control fruits. ) for control fruits. The ) for control -1 -1 —Vol. 65, No. 2, 2000 —Vol. ) showed an accumulation -1 (n), and control (s) during storage -1 -infiltrated showed significantly -infiltrated showed 3 ) of the experiment, and then sper- ) of the experiment, -treated, 33.69 ± 2.79 nmol g -treated, 33.69 ± 2.79 -1 3 (b) production in peaches treated with 2 100 mg L 3 day, the maximum values were reached: were values the maximum day, in GA ; a significant increase in spermdine values increase in spermdine ; a significant Treatments During Peach Storage . . . . Storage Peach During Treatments th -1 3 3 JOURNAL OF FOOD SCIENCE In those fruits that were damaged, initial levels of endoge- In those fruits that In relation to the spermidine contents in damaged peaches In relation to the spermidine ) appeared in putrescine-treated and a significant accumula- a significant and in putrescine-treated ) appeared -1 trescine-treated, and 26.14 ± 2.61 nmol g trescine-treated, and g midine concentrations diminished, showing similar levels to showing similar diminished, midine concentrations peaches at the 14 those found for putrescine-treated treated were significantly higher than those found for control treated were significantly the 10 At peaches. 39.71 ± 1.90 nmol g 290 Putrescine/GA the 14 until diminution a significant Then, nmol g (108.61 ± 8.15 tion was shown appeared during the first 4 d of storage, reaching its maximum storage, reaching during the first 4 d of appeared ± 51.67 nmol g level (438.12 nous putrescine (13.40 ± 0.82 nmol g nous putrescine (13.40 more remarkable effect was obtained in those peaches that were in those peaches effect was obtained more remarkable with GA infiltrated (Fig. 4b), fruits that were GA (Fig. 4b), fruits that during storage for all fruits (Fig. 4a). Putrescine levels in GA during storage for all Fig. 1—Ethylene (a) and CO putrescine 1mM (l), GA at 2 °C. Data are the mean ± SE.

Food Chemistry and Toxicology a loss of fruit quality. During peach storage at 2 °C, treatments zone showed tissue disruption, cellular juice leakage, and brown- with either putrescine or GA3 maintained higher levels of fruit ing that could be related to Maillard reactions, or to enzymatic ox- firmness than those found in control ones, but differences were idation of phenolics substrates by polyphenoloxidase in the only significant between putrescine-treated and control peaches presence of oxygen (Friedman 1996). (Table 1), being this effect clearer when the flesh fruit firmness Putrescine and GA3 treatments inhibited ethylene produc- was determined. Also, in apples (Wang and others 1993), straw- tion during peach storage, putrescine being the most effective. berries (Ponappa and others 1993), and lemons (Valero and oth- This is correlated to an inhibition of the ripening process (Fig. 1a) ers 1998a), polyamines applied before storage improved fruit and to the high peach firmness during storage (Table 1). During texture, as well as postharvest GA3 treatment in lemon fruit. the 1st days of storage, fruit firmness started to decrease while (Valero and others 1998b), apricot (Southwick and Yeager 1995), the ethylene emission was not yet initiated. This is in agreement peach (Southwick and others 1995), and plum (Boyhan and oth- with results reported in other peach varieties, in which the fruit ers 1992). has already begun to soften when ethylene production started Treatments with putrescine and GA3 were also found effective (Tonutti and others 1996). The inhibitory role of exogenous in modifying the fruit susceptibility to be mechanically dam- polyamines on ethylene production has been reported in tomato aged. Thus, the damaged volume and surface, and percentage (Saftner and Baldi 1990), avocado, and pear (Kakkar and Rai of fruit deformation were lower in GA3-treated and significantly 1993), through the inhibition of ACC synthase. lower in putrescine-treated peaches (Table 2). The damaged Unlike most fruits and vegetables (Miller 1992), mechanically Food Chemistry and Toxicology

Fig. 3—Putrescine (a) and spermidine (b) concentrations in peaches Fig. 4—Putrescine (a) and spermidine (b) concentrations in peaches -1 -1 treated with putrescine 1mM (l), GA3 100 mg L (n), and control (s) treated with putrescine 1mM (l), GA3 100 mg L (n), control (s), and during storage at 2 °C. Data are the mean ± SE. then damaged with a compression force of 25 N during storage at 2 °C. Data are the mean ± SE.

Vol. 65, No. 2, 2000—JOURNAL OF FOOD SCIENCE 291 production 2 maintained higher 3 ). For the CO -1 ) of the damaged zone were production rates were mea- 2 2 h -1 would be carried out through the stim- would be carried out , milled to obtain an homogeneous Conclusions 3 2 production determination 2 ) and surface (mm 3 Color was determined using the Hunter Lab System in a Color was determined using the Hunter For each sampling date, peaches were taken out from the Peaches treated with putrescine and GA Peaches treated with fruit firmness during storage, and the respiration rate and ethyl- fruit firmness during The compared with control peaches. ene emission were reduced GA antisenescent role of sured by placing each fruit in a 0.5 L glass jar hermetically sealed with a rubber stopper for 1 h. For ethylene, 1 mL of the holder atmosphere was withdrawn with a gas syringe, and the ethylene was quantified using a gas chromatographer (GC, Waldbronn, GmbH, 5890A, Hewlett-Packard Hewlett-Packard equipped with a flame ionization detector and a 3-m Ger.), stainless steel column with an inner dia of 3.5 mm containing activated alumina of 80/100 mesh. The column temperature was 70 ºC, and injector and detector temperatures were 110 ºC. Results were expressed in nanolitres of ethylene released per gram of tissue per h (nL g sample of each fruit, and then stored at -20 °C until sample of each fruit, and then stored fruits were sam- polyamines were analyzed. Five nontreated following the pled to determine the initial stage after picking, same procedures as above (day 0). calculated. Peel and flesh of the damaged zones were taken calculated. Peel and flesh of the damaged out, frozen in liquid N ulation of spermidine levels during storage. In addition, the levels during storage. In addition, ulation of spermidine the susceptibility of treatments were also effective in reducing Mechanical stress in the fruits to be mechanically damaged. rather than to the peaches led to increased spermidine levels, production. ethylene emission and the respiration rate Color determination Ethylene and CO rate, another sample of 0.5 mL of the same atmosphere was withdrawn and quantified using a GC (Shimadzu GC 14A), with a catarometric detector and a 3-m stainless steel column with an inner diameter of 3.3 mm containing Chromosorb 102. Minolta colorimeter CR200 model (Minolta Camera Co., Osaka, Minolta colorimeter CR200 model (Minolta “a” and “b”, ex- Japan). The ratio between the parameters of 3 determina- pressed as “a/b” was measured as the means tions for each fruit along the equatorial axis. chamber and then allowed to reach room temperature (20°C) during 1 h. The ethylene and CO ally determined. To evaluate the magnitude of the damage, evaluate To ally determined. determined, and the dia and height of the damaged area were volume (mm tems. In many cases, gibberellin application is followed by an in- followed is application gibberellin In many cases, tems. biosyn- of their activities and in the levels in polyamine crease and Valero and others 1994; (Béranger-Novat thetic enzymes of the rela- mechanism although the underlying others 1998b), is still and polyamine metabolism gibberellins tionship between control In damaged deserves further investigation. unclear and during 4b) increased markedly levels (Fig. fruits, spermidine from of an active metabolism could be the result storage, which in since putrescine levels were lower putrescine to spermidine, to the nondamaged fruit. From the damaged zone compared inferred that the mechanical stress could these results, it can be re- the spermidine levels as a physiological induce an increase in sponse. treatments, but treatments, 3 , and then milled to 2 —Vol. 65, No. 2, 2000 —Vol. emissions were individu- 2 L., cv. Babygold 6) fruits were har- 6) fruits were Babygold L., cv. . Tween-20 (0.2% v/v) was added to all Tween-20 . 3 GA productions were measured. Three individ- Treatments During Peach Storage . . . . Storage Peach During Treatments -1 2 Material and Methods 3 Prunus persica Prunus -treated peaches showed a significant increase in spermi- -treated peaches showed a significant increase JOURNAL OF FOOD SCIENCE 3 Two hundred fruits were picked from peach trees. Once in Once peach trees. picked from fruits hundred were Two Identical treatments were made on the same number of Peach ( Peach GA Endogenous putrescine levels showed a gradually increase in Endogenous putrescine the laboratory, 75 peaches were selected in accordance with 75 peaches were the laboratory, Then, they were equatorial dia, and weight. their color, for the following grouped at random into 3 lots of 25 fruits (2) 1 mM putrescine; treatments: (1) control (distilled water); and (3) 100 mg L vested from a commercial farm in Murcia (Spain) at the stage vested from a commercial farm in Murcia firm fruits. The char- of commercial ripening: yellow color and weight 132.57 ± 3.66 acteristics of the fruits were the following: 0.03 ± 0.01, total g, dia 63.1 ± 0.82 mm, color (a/b parameter) (TA) acidity soluble solids (SSC) 13.25 ± 0.27, and titratable 0.46 ± 0.01. the solutions to improve the absorption of the chemicals. The treatments were performed by placing the fruits in 5 L of the corresponding solution, and applying pressure (200 mm Hg) for 8 min. Following infiltration, the fruits were placed on Kraft paper and allowed to dry before storage at 2 °C in a tempera- in permanent darkness and with a chamber, ture-controlled relative humidity of 90%. After 1, 2, 4, 10, and 14 d, 5 fruits for each treatment were sampled. They were weighed, and the ethylene and CO fruits, which were damaged with 25 N compression forces in 2 equatorial zones at 90º, 24 h after the treatments were performed, and then stored at 2 °C as above described. A beveled holder fixed the fruit and prevented bruising of the opposite side. After 1, 2, 4, 10, and 14 d, 5 fruits for each treatment were sampled, and the ethylene and CO obtain an homogeneous sample for each fruit and stored at - 20 °C until polyamines were analyzed. Plant material ual discs from each fruit (peel plus flesh) of 12-mm dia were sampled, immediately frozen in liquid N nondamaged peaches during storage (Fig. 3a), showing no dif- during storage (Fig. 3a), showing no nondamaged peaches This increase in the putrescine con- ferences among treatments. as of the low storage temperature, tents could be a consequence and others 1997), (Valero peach ‘Maycrest’ in has been reported (Serrano and others 1997), and zucchini mature green pepper others 1998). These reports indicate that squash (Serrano and would be a protective response the increase in putrescine be or that putrescine itself could against the low temperatures kind of stress. In the mechanically dam- the consequence of this in endogenous putrescine during storage aged zone, an increase the levels significantly higher in treated was also found, being peaches than in controls (Fig. 4a). the mechanism of this suppression can not be deduced from our can not be deduced of this suppression the mechanism experiment. 292 Putrescine/GA or ethyl- rate respiration increase their did not peaches damaged damage of the consequence as a during storage ene production and in papaya (Quintana 2), as has been reported (Fig. 1 and 1993). (Ketsa and Koolpluksee and in mangosteen Paull 1993) in eth- to suppress the reduction force seemed The compression and GA caused by putrescine ylene production dine levels early in storage (Fig. 3b). The effect of gibberellins on dine levels early in storage (Fig. 3b). The in a variety of sys- polyamine metabolism has been examined

Food Chemistry and Toxicology The column temperature was 55 ºC, and injector and detector Universal Assay Machine. The sphere traveled at 20 mm min-1 temperatures were 110 ºC. Results were expressed in milli- until the 25 N force was achieved after contacting the fruit. -1 - grams of CO2 released per kilogram of tissue per h (mg kg h This damage produced a stretch deformation on peach (mm). 1). The results were expressed as the percentage of fruit deformation, that was the ratio between stretch deformation and fruit Total soluble solids concentration (SCC) and diameter multiplied by 100. This treatment was made in du- titratable acidity (TA) determination plicate for each fruit. TA was determined by potentiometric titration with 0.1 N NaOH up to pH = 8.1 using 1 mL of diluted juice in 25 mL dis- Bruising measurement tilled H2O. The results were expressed as g of malic acid per Diameters and heights of the mechanical damaged zone 100 g fresh weight. Two measurements were made from each produced by the compression force of 25 N were measured fruit. Total SSC were determined by a P20 RL2 refractometer at with a ruler to determine bruising volume (mm3) and surface 20 °C. Three determinations were made from each fruit. (mm2). The measurements were made for each sampling date, and the results were expressed as the mean ± SE of all togeth- Firmness determination er. Firmness was carried out in nondamaged fruits on the basis of 2 parameters, one of them as indicator of the whole fruit Polyamine analysis firmness (deformation slope), and the other one as indicator Two extractions of polyamines were made from each peach. of the flesh texture (Magness-Taylor firmness). Deformation One g fresh tissue was extracted with 10 mL of 5% cold perchlo- slope was measured using a flat steel plate mounted on a Uni- ric acid. 1,6 Hexanediamine (100 nmol g-1) was added as inter- versal Assay Machine Lloyd, model LR5K (Lloyd Instruments, nal standard. The homogenate was then centrifuged for 30

Segensworth, U.K.) interfaced to a personal computer. For min at 20000 H g. Free polyamines left in the supernatant were Food Chemistry and Toxicology each fruit, the dia was measured and then a force that pro- benzoylated and derivatives were analyzed by high pressure voked a deformation of 1% of the fruit diameter was applied. liquid chromatography. The elution system consisted of Results were expressed as the ratio between the deformation MeOH/H2O (64:36) solvent, running isocratically with a flow produced and the fruit dia (N mm-1) multiplied by 100. Two rate of 0.8 mL min-1. The benzoyl-polyamines were eluted measurements were made on 2 equatorial fruit zones at 90°. A through a reversed-phase column (LiChroCart 250-4,5 m) and beveled holder prevented bruising of the opposite side. The detected by absorbance at 254 nm. A relative calibration pro- machine was prepared to travel at 20 mm min-1 after contact- cedure was used to determine the polyamines in the samples, ing the peel. Magness-Taylor firmness was recorded using 5- using 1,6 hexanediamine as the internal standard and stan- mm dia probe mounted on the same Universal Assay Ma- dard curves ranged from 1 to 500 nM. The calibration curves chine. The fruits were peeled off on 2 equatorial fruit zones at were y = 0.048 H –250.71, r = 0.9998 (for putrescine), and y = 90° and 2 measurements were made. A beveled holder pre- 0.039 H – 291.63, r = 0.9998 (for spermidine). vented bruising of the opposite side. The machine was prepared to travel at 20 mm min-1 for 10 mm after contacting the Statistical design flesh. The machine determined the maximum force of the A two-factor analysis of variance was made to determine flesh penetration and the results were expressed in N. the effect of treatments and storage time on ethylene, CO2, firmness, bruising volume and surface, and polyamines. Compression treatment Mean comparisons were performed using Honestly Significant For each fruit, the dia (mm) was measured and then a me- Difference (Tukey’s test) to examine differences between chanical damage with a compression force of 25 N was ap- treatments and storage time. All analyses were performed plied, using a steel sphere of 20-mm dia mounted on the same with SAS statistical software package (SAS Institute 1988).

References putrescine and calcium treatments on reducing mechanical damage and polyamines Amorós A, Serrano M, Riquelme F, Romojaro F. 1989. Levels of ACC and physical and and ABA levels during lemon storage. J. Sci. Food Agric. 79: 1589-1595. chemical parameters in peach development. J. Hort. Sci. 64: 673-677. Miller AR. 1992. Physiology, biochemistry and detection of bruising (mechanical Béranger-Novat N, Monin J, Martin-Tanguy J. 1994. Polyamines and their biosynthet- stress) in fruits and vegetables. Postharvest News Inform. 3: 53-58. ic enzymes in dormant embryos of the spindle tree (Euonymus europaeus L.) and in Ponappa T, Scheerens JC, Miller AR. 1993. Vacuum infiltration of polyamines increas- dormancy break obtained after treatment with gibberellic acid. Plant Sci. 102: 139- es firmness of strawberry slices under various storage conditions. J. Food. Sci. 58: 145. 361-364. Quintana MEG, Paull RE. 1993. Mechanical injury during postharvest handling of Boyhan GE, Norton JD, Abraham BR, Pitts JA. 1992. GA3 and thinning affect fruit quality and yield of ‘AU-Rubrum’ plum. HortScience 27: 1045. ‘Solo’ papaya fruit. J. Am. Soc. Hort. Sci. 118: 618-622. Friedman M. 1996. Food browning and its prevention: an overview. J. Agric. Food Robertson JA, Meredith FY, Lyon BG, Chapman, G. W. 1993. Comparison of quality Chem. 44: 631-653. characteristics of three nonmelting clingstone peach selections. J. Food. Quality. 16: Kakkar RK, Rai VK. 1993. Plant polyamines in flowering and fruit ripening. Phy- 197-207. tochemistry 33: 1281-1288. Saftner RA, Baldi BG. 1990. Polyamine levels and tomato fruit development: possible Ketsa S, Koolpluksee M. 1993. Some physical and biochemical characteristics of dam- interaction with ethylene. Plant Physiol. 92: 547-550. age pericarp of mangosteen fruit after impact. Postharvest Biol. Technol. 2: 209-215. Serrano M, Martínez-Madrid MC, Martínez G, Riquelme F, Petrel MT, Romojaro F. 1996. Khader SESA. 1992. Effect of gibberellic acid and vapour guard on ripening amylase Review: Role of polyamines in chilling injury of fruit and vegetables. Food Sci. and peroxidase activities and quality of mango fruits during storage. J. Hort. Sci. 67: Technol. Int. 2: 195-199. 855-860. Serrano M, Martínez-Madrid MC, Petrel MT, Riquelme F, Romojaro F. 1997. Modified Leiting VA, Wicker L. 1997. Inorganic cations and polyamines moderate pectinesterase atmosphere packaging minimizes increases in putrescine and abscisic acid levels activity. J. Food Sci. 62: 253-255.. caused by chilling injury in pepper fruit. J. Agric. Food Chem. 45: 1668-1672. Leliévre JM, Latché A, Jones B, Bouzayen, M. and Pech, J. C. 1997. Ethylene and fruit Serrano M, Martínez-Madrid MC, Romojaro F, Riquelme F. 1998. CO2 treatment of zuc- ripening. Physiol. Plant. 101: 727-739. chini squash reduces chilling-induced physiological changes. J. Agric. Food Chem. Looney NE, Granger RL, Chu CL, McArtney SJ, Mander LN, Pharis RP. 1992. Influences 46: 2465-2468. Southwick SM, Weis KG, Yeager JT. 1995. Controlling cropping in ‘Loadel’ cling peach of gibberellins A4, A4+7, and A4+iso-A7 on apple fruit quality and tree productivity. I. Effects on fruit russet and tree yield components. J. Hort. Sci. 67: 613-618. using gibberellin: effects on flower density, fruit distribution, fruit firmness, fruit Maness NO, Brusewitz GH, McCollum TG. 1992. Impact bruise resistance comparison thinning, and yield. J. Amer. Soc. Hort. Sci. 120: 1087-1095. among peach cultivars. HortScience 27: 1008-1011. Southwick SM, Yeager JT. 1995. Use gibberellin formulations for improved fruit firm- Martínez-Romero D, Valero D, Serrano M, Riquelme F. 1999. Effects of postharvest ness and chemical thinning in ‘Patterson’ apricot. Acta Hort. 384: 425-429.

Vol. 65, No. 2, 2000—JOURNAL OF FOOD SCIENCE 293 in Agricultural & Food Chemistry. Trivandrum, India: Research Signpost. p 39-55 Research Signpost. India: Trivandrum, & Food Chemistry. Agricultural in 14:285-289. J. Food. Quality. compression. and by impact, vibration, caused 18: 265-278. Quality. bruising. J. Food. changes in production and texture and calcium influences ethylene of polyamines Hort. Sci. 118: 801-806. apples. J. Amer. Soc. ‘Golden Delicious’ Authors Martínez-Romero, Valero, Serrano, Burló, Carbonell are with the Carbonell are Burló, Serrano, Valero, Martínez-Romero, Authors Hernández), (Universidad Miguel Superior de Oriuela Escuela Politécnica Orihuela (Alicante), Spain. Authors Burgos Ctra. Beniel km. 3.2, E-03312 del the Centro de Edafología y Biología Aplicada and Riquelme are with inquiries to Address Spain. E-30080 Murcia, 1, La Fama, Av. (CSIC), Segura (E-mail: author Valero [email protected]). Vergano PJ, Testin RF, Newall JWC. 1991. Distinguishing among bruises in peaches among Distinguishing JWC. 1991. Newall RF, Testin PJ, Vergano loss cost for peach impact 1995. Damage T. Trezza JWC, Newall RF, Testin PJ, Vergano CE. 1993. Postharvest infiltration Sams JA, Kramer GF, Abbott WS, Conway CY, Wang 12/1/99; accepted 12/28/99. received 6/24/99; revised MS 1999-0639 L. Prunus persica —Vol. 65, No. 2, 2000 —Vol. L. Burm Cv. Verna). J. Agric. Food Chem. 46: Agric. Food J. Verna). L. Burm Cv. L. Batsch). J. Hort. Sci. 71: 141-147. L. Batsch). J. Treatments During Peach Storage . . . . Storage Peach During Treatments Citrus lemon 3 Prunus persica JOURNAL OF FOOD SCIENCE cultivars of peach ( cultivars of peach ulation. Physiol. Plant. 100: 664-674. Physiol. Plant. ulation. treatment with putrescine and calcium on endogenous polyamines, firmness, and on endogenous polyamines, putrescine and calcium treatment with in lemon ( abscisic acid Recent Research Development In: Pandalai S, editor. review. A post-harvest of fruits: and physicochemical changes in low-temperature-stored peach ( changes in low-temperature-stored and physicochemical 45: 3406-3410. Agric. Food Chem. Maycrest). J. Cv. in two mandarin cultivars. HortScience 33: 1220-1223. external mechanical bruising and heat treatment effects on polyamines, abscisic acid and firmness in lemons. J. on polyamines, abscisic acid and firmness in lemons. and heat treatment effects Food Sci. 63: 611-615. 2102-2109. 294 Tonutti P, Bonghi C, Ramina A. 1996. Fruit firmness and ethylene biosynthesis in three in ethylene biosynthesis firmness and A. 1996. Fruit Bonghi C, Ramina P, Tonutti Putrescine/GA reg- and Polyamine metabolism C. 1997. A, Masgrau Borrell T, Altabella AF, Tiburcio Valero D, Martínez-Romero D, Serrano M, Riquelme F. 1998a. Influence of postharvest 1998a. Influence D, Serrano M, Riquelme F. D, Martínez-Romero Valero 1999. Polyamines roles on the F. D, Martínez-Romero D, Serrano M, Riquelme Valero Valero D, Serrano M, Martínez-Madrid MC, Riquelme F. 1997. Polyamines, ethylene, F. Martínez-Madrid MC, Riquelme D, Serrano M, Valero 1998c. Polyamine response to F. D, Martínez-Romero D, Serrano M, Riquelme Valero Valero D, Martínez-Romero D, Serrano M, Riquelme F. 1998b. Postharvest gibberellin 1998b. M, Riquelme F. Martínez-Romero D, Serrano D, Valero

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