International Journal of Engineering & Technology, 7 (4.14) (2018) 253-256

International Journal of Engineering & Technology

Website: www.sciencepubco.com/index.php/IJET

Research paper

Physicochemical Properties and Sensory Evaluation of Banana Peel Biscuits

Syarifah Khadijah Syed Abu Bakar 1, Noorlaila Ahmad 1,2 and Fadhilah Jailani 1*

1 Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Malaysia 2 Malaysia Institute of Transport, Universiti Teknologi MARA, 40450 Shah Alam, Malaysia *Corresponding author E-mail: [email protected]

Abstract

Banana peels consist of valuable bioactive compounds and yet remain underutilised. This study investigated the effect of banana peel flour incorporation into biscuit formulation. The physicochemical properties and sensorial acceptability of biscuits produced at the different level of substitution (0%, 10%, 20%, 30% and 40%) of Banana Peel Flour (BPF) were determined. The ash content (1.66% to 2.11%), moisture content (2.13% to 2.66%), fat content (24.2% to 30.7%) and total dietary fiber content (1.83 g/100g to 4.70 g/100g) in biscuits increased when the level of BPF substitution increased. The texture analysis demonstrated that BPF-containing biscuits had significantly higher value in hardness (1071.15 to 1300.61g) than control biscuit (992.69 g). İn contrast, the study showed a significant decrease in fracturability, lightness, width and height as the concentration of BPF increased. Sensory evaluation indicated that biscuit incorporated with BPF up to 20% level did not affect the appearance, taste, texture and overall acceptability ratings by the panelists. İn conclusion, BPF can be used as a functional ingredient and partially substituted flour in biscuit production.

Keywords: Banana Peel, Biscuits, Functional Properties, Physical Properties, Total Dietary Fiber

more accepted by consumers [6]. The use of by-product from 1. Introduction fruits has been investigated by the previous researcher such as apple pomace and orange pomace. Apple pomace is a rich source Fruit processing industry is marked as high rate of residue of polyphenols, shown good anti-proliferative and antioxidant producer. Several by-products such as peel, stalk, seed, crashed activity while orange pomace contributes the dietary fiber content pulp still contains huge amount of biopolymers and bioactive of cookies [4]. molecular compounds that are considered as nutritional loss [1]. The purpose of this study was to determine the chemical Banana peel possesses 40% of fresh banana and plantain and this composition and physical properties of biscuits supplemented by huge amount of waste can cause an environmental problem if it is banana waste (peel) as a functional ingredient. The effects of their not discarded properly [2]. However, this by-product can be incorporation at different levels (0, 10, 20, 30 and 40 %) on reused to minimize the waste and create a new source of food as sensory parameters of biscuits was also determined. vegetable and fruit are rich in protein, fiber and mineral. In addition, it has high water and oil holding capacity which is beneficial to develop a low cost and calorie product [3]. 2. Materials and methods Nutritionist also suggested to consume food with low fat content and calories as well as rich in antioxidant and dietary fiber 2.1. Preparation of banana peel flour and biscuits contents because of their ability in lowering the cholesterol and preventing constipation and cardiovascular disease [4]. Unripe Pisang Berangan (Musa spp. AA) was collected from an Banana peel is a good source of dietary fiber as it consists of 50% orchard in Klang, Selangor, Malaysia. The banana was washed in dessert and plantain banana peels [2]. According to Aslam et al. and peeled, then separated from the pulp. The peel was treated (2014), dietary fiber is well-known in reducing the risk of diseases with 0.2% of citric acid and 0.2% of sodium metabisulfite, then such as constipation, irritable colon, colon cancer, cardiovascular dried at 60 ᵒC for ±12 hours, ground and the flour was sieved diseases, diverticulosis and diabetes [4]. Therefore, dietary fiber through a 40 mesh screen using an American Standard Test should be included in food as dietary fiber is beneficial to human (ASTM) series. The biscuits were formulated with different health. concentrations of BPF suc as 0, 10, 20, 30 and 40%. The basic Biscuits are one of the most popularly consumed products. ingredients used for the preparation of biscuits consist of butter, It is consumed by people around the world mainly because it wheat flour, banana peel flour, castor , corn flour, cocoa and portability, ready to eat, good nutritional quality, affordable, salt. Butter was mixed until light and fluffy. Then, sugar was longer shelf life and available in various flavour and taste [5]. added and mixed for about 2 minutes. Wheat flour, banana peel According to Maria et al. (2014), a mixture of flour made from flour, corn flour, cocoa powder, and salt were added slowly and unconventional products with wheat flour improves the nutritional formed . The dough was rolled into 10 mm, moulded and quality of cookies, improve their palatability and making them baked for 10-12 minutes at 160 ᵒC.

Copyright © 2018 Authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

International Journal of Engineering & Technology 254

2.2. Chemical analysis content compared to sweet orange peel and lemon peel (2.6 g/100g and 2.5 g/100g) [11]. The protein content of biscuits Proximate analysis: Moisture, ash, fat, crude protein content of ranged between 3.30% and 3.77% which shows a decreasing trend the BPF and biscuits were determined using method described by as the quantity of BPF increases. This study is similar with Aw, AOAC (2000) and the carbohydrate content was calculated by Odan & Ranwala (2014), biscuit substituted with the highest difference [7]. The results were expressed as a percentage. amount of kohila powder as a dietary fibre source shows the Total Dietary Fiber (TDF): Enzymatic-gravimetric method 991.43 lowest protein content [12]. The decrease of protein content may was utilized for this method [8]. be due to the reduced quantity of wheat flour used in making biscuit as wheat flour has high gluten protein content. 2.3. Physical properties Carbohydrate content of biscuits incorporated with BPF were significantly (p<0.05) low compared to control. Control (68.25%) Colour measurement: The colour of the biscuits was measured biscuit exhibited the highest carbohydrate content while 40% BPF using CR400 Konica Minolta Chroma Meter (Osaka, Japan). The (61.23%) had the lowest carbohydrate content. This reduction may colour scale of CIELAB parameters used was L*a*b*. be due to the high amount of other compositions. The result was Texture profile analysis: The hardness and fracturability of the similar with the previous study in which the addition of high level biscuit were measured using TA-XT2i texture analyser with 0.25” of defatted coconut flour as a dietary fibre source reduced the diameter of the spherical probe. The setting for the instrument was carbohydrate content of biscuits due to the different quantity of 2.0 mm/s for pre-test speed, 1.0 mm/s and 5.0 mm/s for test and ash, protein, fat and moisture content of defatted coconut flour post-test speed respectively, compression distance was 3.0 mm/s [13]. and type of trigger was set as auto. Width, thickness and spread ratio: Physical characteristic of Table 1: Proximate analysis of biscuits incorporated with banana peel biscuits were measured according to Ajila et al. (2008) where the flour Level width of the biscuits was measured by laying six biscuits edge-to- Moisture Ash Fat Protein CHO of edge then, it was rotated 90 ᵒ and the width was remeasured [1]. (%) (%) (%) (%) (%) BPF Thickness (T) of biscuits was measured by stacking six biscuits on 2.13 ± 1.66 ± 24.2 ± 3.77 ± 68.25 ± top of one another and taking the average of six biscuits. Width 0 % a a e a a and thickness were reported in millimetre. The spread ratio was 0.30 0.42 0.17 0.06 0.30 calculated by dividing the width by thickness. 2.39 ± 1.66 ± 26.7 ± 3.77 ± 65.48 ± 10 % a a d a b 0.53 0.30 0.26 0.15 0.63 2.4. Sensory evaluation 2.45 ± 1.73 ± 27.1 ± 3.70 ± 65.69 ± 20 % a a c a b 0.48 0.58 0.10 0.10 0.15 Biscuit samples were assessed for sensory evaluation with 2.52 ± 1.86 ± 27.8 ± 3.60 ± 64.23 ± parameters of appearance, colour, texture, taste and overall 30 % a a b a c acceptability. Sensory quality characteristics were evaluated by 30 0.31 0.12 0.26 0.20 0.36 2.66 ± 2.11 ± 30.7 ± 3.30 ± 61.23 ± untrained panelistss using a 9-point Hedonic scale where 9 = like 40 % a a a b d extremely; 8 = like very much; 7 = like moderately; 6 = like 0.65 0.50 0.20 0.20 0.22 slightly; 5 = neither like nor dislike; 4 = dislike slightly; 3 = Values represent the mean ± standard deviation. Different superscript dislike moderately; 2 = dislike very much; 1 = dislike extremely. letters indicate significant differences (p<0.05). CHO= carbohydrate.

2.5. Statistical analysis 3.2. Total dietary fiber content of biscuits

Results were expressed as mean values and standard deviation of Total dietary fibre (TDF) content of biscuits is given in Table 2. three (3) determinations. The obtained data were the analysed Based on the result, TDF content was significantly (p<0.05) using a one-way Analysis of Variance (ANOVA) using the increased with the increased level of BPF substituted in biscuits. Statistical Package for Social Science (SPSS) to test the level of The value of TDF content in biscuits was ranged between 1.85% significance (p<0.05). Duncan New Multiple Range Test was used and 4.70%. This study is supported by Gunathilake & Yalegama to separate the means where significant differences existed. (2009), who stated that partial substitution of wheat flour by other locally raw ingredient flour is necessary to enhance the nutritional value of since refined wheat flour alone is not a good source 3. Results and discussion of fiber [14]. A study conducted by Ajila, Leelavathi & Rao (2008) also shows that TDF content of biscuits increased from 3.1. Proximate analysis 6.5% to 20.7% with the incorporation of mango peel powder [1].

Table 1 shows the proximate compositions of biscuits Table 2: Total dietary fiber content of biscuits incorporated with banana incorporated with BPF. Moisture and ash content of biscuits peel flour shows an increasing trend with no significant (p<0.05) difference Level of BPF TDF (g/100g) e as the level of BPF increased. The moisture content of biscuits 0 % 1.83 ± 0.56 ranged between 2.13% to 2.66%. It was established that biscuit d 10 % 2.43 ± 0.15 should have a low moisture content of 1-5%, excluding any c moisture from fillings or icing [9] because high moisture can 20 % 3.07 ± 0.15 b attract mold, insects and bacteria, resulting in deterioration of 30 % 3.33 ± 0.15 product during storage time [10]. There were no significant a 40 % (p<0.05) difference in ash content between control and BPF 4.70 ± 0.20 biscuits but the ash content showed an increasing trend from Values represent the mean ± standard deviation. Different superscript 1.66% to 2.11% as amount of BPF increased. There was letters indicate significant differences (p<0.05). significant (p<0.05) difference observed in the fat, protein and carbohydrate content in biscuits. The fat content of biscuits 3.3. Physical properties of biscuits increased as the level of BPF increased. This may due to the high The colour of food product is one of the important factors in content of fat in banana peel flour. According to Wachirasiri, determining the acceptance of consumer. Table 3 shows the colour Julakarangka & Wanlapa (2009), banana peel has greater fat International Journal of Engineering & Technology 255 of biscuits with different level of BPF (0%, 10%, 20%, 30% and According to Jauharah, Rosli & Robert (2014), a biscuit with the 40%). The increase of BPF in biscuit significantly (p<0.05) highest value of spread ratio is more desirable because it shows decrease the L* value. Control biscuit had significantly highest L* the limit of increase width of biscuit during [9]. value compared to BPF enriched biscuits. Drying of banana peel is the major reason for the dark brown colour of BPF. The formation Table 5: Width, thickness and spread ratio of biscuits of the dark brown colour of dried banana peel might be Sample Width (mm) Thickness (mm) Spread factor Control 54.00 ± 0.25 a 7.88 ± 0.13 a 6.86 ± 0.10 c contributed by the and enzymatic browning a a c during the drying process of the peel since banana peel contains 10% BPF 53.67 ± 1.04 7.63 ± 0.13 7.04 ± 0.20 20% BPF 52.92 ± 1.44 a 7.21 ± 0.19 b 7.35 ± 0.31 bc protein, fructose, glucose and enzymes like polyphenol oxidase. a b b 30% BPF 52.42 ± 2.38 6.92 ± 0.14 7.58 ± 0.38 Thus, affecting the L* value of biscuits [16]. It was found that the 40% BPF 51.25 ± 1.25 a 6.13 ± 0.21 c 8.37 ± 0.36 a value of a* and b* in biscuits decreased with the increased level of Values represent the mean ± standard deviation. Different superscript BPF. letters indicate significant differences (p<0.05).

Table 3: Colour measurement of biscuits 3.4. Sensory evaluation Sample L a b Control 55.48 ± 1.28 a 11.48 ± 0.75 a 25.03 ± 1.15 a b b b Sensory evaluation was conducted to determine panelists 10% BPF 50.74 ± 0.56 10.15 ± 0.39 23.29 ± 0.23 acceptance of biscuits with different level of BPF. The result 20% BPF 45.06 ± 0.87 c 9.14 ± 0.72 c 21.84 ± 0.48 c 30% BPF 43.45 ± 0.45 d 7.88 ± 0.16 d 21.37 ± 0.41cd shows that there were no significant differences in appearance, 40% BPF 41.48 ± 0.19 e 6.65 ± 0.17 e 20.47 ± 0.30 d taste and texture between control biscuits up to 20% incorporation Values represent mean ± standard deviation. Different superscript letters of BPF. Biscuit made from 30% and 40% were not preferred by indicate significant differences (p<0.05). panelists. This might be due to the higher level of BPF gave unpleasant taste and darken the colour of biscuits as shown in Table 4 shows the hardness and fracturability of biscuits Table 6. Likewise, biscuits become darker when incorporated with incorporated with BPF. Control (0%) biscuit had the significantly mango waste due to the enzymatic browning activities [1] and the (p<0.05) lowest hardness value compared to biscuits with 30% addition of 15% of fiber from citrus peel give a bitter taste to the and 40% of BPF. The hardness of the biscuit might be related to biscuits [17]. For overall acceptance, there was no significant the development of the gluten network as gluten promotes the different between control biscuits and 10% and 20% addition of network by attracting the water molecules [4]. According to [1], BPF. The quality and sensory properties of biscuits incorporated high water content in dough produced an extensive gluten with BPF is higher than biscuits made from other fruit waste. [4] structure and consequently increases the hardness of biscuits. It and [1] reported that biscuits made from mango peel were was reported that the hardness of muffin incorporated with peach accepted by panelists at 10% of addition of mango peel flour fibre increased due to reduce number of air pockets and increase while [17] stated that 5% of addition of citrus peel was preferred in density [9]. The crispiness of biscuit can be determined by by the panelists. fracturability of product. The highest score of the product indicates the lower crispiness. Based on the results, the Table 6: Sensory evaluation score of biscuits Sampl Appeara Text Overal fracturability of biscuits decreased from 16.32g to 13.53g. This Colour Taste value shows that biscuits incorporated with high BPF (20%, 30% e nce ure l 7.30 ± 7.50 ± 7.30 ± 7.47 7.43 ± and 40%) are crispier than control (0%) biscuit. 0% a a a a a 1.15 1.01 1.37 ± 1.04 0.94 7.07 ± 6.90 ± 6.70 ± 7.17 6.83 ± Table 4: Texture profile of biscuits 10% 0.83 a 1.03 ab 1.06 ab ± 1.09 a 1.02 ab Sample Hardness (g) Fracture (g) 6.73 ± 6.57 ± 7.20 ± 7.23 7.27 ± c a 20% Control 992.69 ± 112.20 16.32 ± 0.24 1.48 ab 1.36 bc 1.32 a ± 0.86 a 0.98 a 10% BPF 1071.15 ± 94.54 bc 15.01 ± 0.56 ab abc ab 6.10 ± 5.90 ± 5.43 ± 6.30 5.93 ± 20% BPF 1124.53 ± 51.11 14.84 ± 0.97 30% b cd c b c ab b 1.52 1.47 1.94 ± 1.60 1.57 30% BPF 1203.44 ± 46.81 14.20 ± 0.79 6.33 ± 5.80 ± 6.03 ± 6.53 6.43 ± a b 40% 40% BPF 1300.61 ± 55.71 13.53 ± 1.89 1.52 b 1.60 d 1.59 bc ± 1.04 b 1.14 b c Values represent mean ± standard deviation. Different superscript letters Values represent mean ± standard deviation. Different superscript letters indicate significant differences (p<0.05). indicate significant differences (p<0.05).

Influence of BPF on the physical characteristics of biscuits prepared using 0, 10, 20, 30 and 40% of BPF was evaluated. 4. Conclusion Physical characteristics of biscuits such as thickness, width and spread ratio were affected slightly with the increased level of BPF The data obtained from the present study indicates that (Table 3). The width of the biscuits was slightly decrease but no substitution of wheat flour with BPF significantly increases the fat significant (p<0.05) difference was observed with the control and total dietary fiber content of biscuits. The protein content of biscuit. The thickness of biscuits incorporated with BPF was biscuits reduced as percentage of BPF increased and the amount of comparable with control biscuit. Control biscuit was significantly wheat flour used decreased. Besides, the addition of fibre also thicker than a biscuit with 10, 20, 30 and 40% of BPF. The influences the physical and sensory acceptance of biscuits. decrease in width and thickness of biscuits may be due to the Increasing the level of BPF in biscuit might increase the hardness dilution of gluten protein in wheat flour [1] because as the level of and darken the colour of biscuits. In addition, substitutions of BPF BPF increase, the amount of wheat flour used in biscuits decrease. reduced the width and increased the spreading factor of the High thickness in control biscuits gave the lowest spread ratio. biscuits. Biscuits of acceptable quality can be prepared, by The spread factor of control (6.86) biscuit was significantly lowest substituting wheat flour with up to 20% BPF. Thus, BPF is and compared to BPF biscuit. There was an increasing trend of suitable to be supplemented in biscuit formulation as partial spread factor as the level of BPF incorporated in biscuit was substitution of wheat flour. It also can be utilized as a functional increased. However, the increased level of BPF in the biscuit was ingredient in formulated bakery products because of it’s low-cost, not significantly affected by the spreading factor of biscuits. The ability to improve the nutritional quality and maintain the physical findings of this study are in agreement with the study conducted quality of biscuit. by Gupta & Tiwari (2014), who stated that the increase of wheat in biscuit not affected the spread ratio of biscuit [15]. International Journal of Engineering & Technology 256

Acknowledgement

The authors would like to acknowledge Ministry of Higher Education (MoHE) and Universiti Teknologi MARA (UiTM) Shah Alam for granting this project (Grant No: 600-RMI/FRGS 5/3 (27/2015).

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