Evaluation of Physicochemical and Organoleptic Properties of Dried Apple Slices with Whey Protein Isolate-Inulin Conjugates and Apple Extract

Document Type : Research Article


1 Associate Professor, Department of Food science and technology, Gorgan University of Agricultural Sciences and Natural Resources, Golestan , Iran

2 Faculty of Food Science & Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran


In this study, the effect of whey protein isolate-inulin conjugates (1: 1 and 1: 2) and apple pulp extract (200 and 300 ppm) as alternatives to sodium metabisulfite was used for drying of apple. Polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) were performed to perform the Millard reaction. Also the content of total phenol, total flavonoids, antioxidant activity by DPPH and total antioxidant methods, water activity, amount of soluble solids, color index, activity of peroxidase enzyme (POD) and polyphenol enzyme Oxidase (PPO), structure analysis as well as sensory evaluation of the dried apple samples coated with whey protein isolate-inulin conjugates and apple pulp extract were investigated. The results of this study showed that the samples coated in 1% of whey protein isolate - inulin (1: 2) containing 300 ppm of apple extract had higher phenolic and flavonoid compounds than the other samples. Also, the concentration of 1% whey protein isolate - inulin (1: 2) containing 300 ppm of apple pulp extract had higher score of aroma, taste, color, texture and acceptability attributes. The results showed that of whey protein isolate-inulin conjugates and apple pulp extract showed strong inhibition against the browning of the dried apple. Therefore, it can be used as a preservative to prevent browning in apple slices as a substitute for sodium metabisulfite.

Graphical Abstract

Evaluation of Physicochemical and Organoleptic Properties of Dried Apple Slices with Whey Protein Isolate-Inulin Conjugates and Apple Extract


  • The samples coatedwith whey protein isolate-inulin conjugates and apple pulp extract had high phenolic and flavonoid compounds.
  • Whey protein isolate -inulin conjugates and apple pulp extract showed the strong inhibition against the browning of the dried apple.
  • Whey protein isolate -inulin conjugates and apple pulp extract can be used as a substitute for sodium metabisulfite in the processing of dried products.


Main Subjects

[1] Gao, K., Zhou, L., Bi, J., Yi, J., Wu, X., & Xiao, M. (2017). Research on the nonenzymatic browning reactions in model systems based on apple slices dried by instant controlled pressure drop drying. Dry. Technol., 35, 1302-1311.
[2] Tepe, T. K., & Tepe, B. (2020). The comparison of drying and rehydration characteristics of intermittent-microwave and hot-air dried-apple slices. Heat Mass Transfer., 56, 3047-3057.‏
[3] Deng, L. Z., Mujumdar, A. S., Zhang, Q., Yang, X. H., Wang, J., Zheng, Z. A., & Xiao, H. W. (2019). Chemical and physical pretreatments of fruits and vegetables: Effects on drying characteristics and quality attributes–a comprehensive review. Crit Rev Food Sci., 59, 1408-1432.‏
[4] Bai, X., Xiao, Q., Zhou, L., Tang, Y., & He, Y. (2020). Detection of sulfite dioxide residue on the surface of fresh cut potato slices using near-infrared hyperspectral imaging system and portable near-infrared spectrometer. Molecules., 25, 1651.‏
 [5] Basiri, S. (2014).The effect of pomegranate peel extract on inhibition of polyphenol oxidase and quality of pacific white shrimp (litopeneous vannamei) during refrigerated storage.  PhD thesis. Gorgan University of Agricultural Sciences and Natural Resources. [In Persian].
[6] Moon, K. M., Lee, B., Cho, W. K., Lee, B. S., Kim, C. Y., & Ma, J. Y. (2018). Swertiajaponin as an anti-browning and antioxidant flavonoid. Food chem., 252, 207-214.‏
 [7] Mulcahy, E.M., Fargier-Lagrange, M., Mulvihill, D.M., & O'Mahony, J.A. (2017). Characterisation of heat-induced protein aggregation in whey protein isolate and the influence of aggregation on the availability of amino groups as measured by the ortho-phthaldialdehyde (OPA) and trinitrobenzenesulfonic  acid (TNBS) methods. Food Chem., 229, 66-74.
[8] De Oliveira, F.C., Coimbra, J.S.D., De Oliveira, E.B., Zuniga, A.D.G., & Rojas, E.E.G. (2016). Food protein-polysaccharide conjugates obtained via the maillard reaction: a review. Crit. Rev. Food Sci. Nutr., 56, 1108-1125.
[9] Muley, A. B., & Singhal, R. S. (2020). Extension of postharvest shelf life of strawberries (Fragaria ananassa) using a coating of chitosan-whey protein isolate conjugate. Food Chem., 329, 127213.
[10] Brito Nogueira, T. B., Silva, T. P., Araújo Luiz, D., Andrade. C. J., Andrade, L. M. Ferreira, M. S.,  & Cavalcante Fai, A. E. (2020). Fruits and vegetable- processing waste. Environ. Sci. Pollut. Res., 27, 18530–18540.
[11] Kuijpers, T. F., van Herk, T., Vincken, J. P., Janssen, R. H., Narh, D. L., van Berkel, W. J., & Gruppen, H. (2014). Potato and mushroom polyphenol oxidase activities are differently modulated by natural plant extracts. J. Agric. Food Chem., 62, 214-221.‏
[12] Perez-Gago, M. B., Serra, M., & Del Rio, M. A. (2006). Color change of fresh-cut apples coated with whey protein concentrate-based edible coatings. Postharvest Biol. Technol., 39, 84-92.
[13] Sukhonthara, S., Kaewka, K., & Theerakulkait, C. (2016). Inhibitory effect of rice bran extracts and its phenolic compounds on polyphenol oxidase activity and browning in potato and apple puree. Food chem., 190, 922-927.‏
[14] Alves, M. M., Gonçalves, M. P., & Rocha, C. M. (2017). Effect of ferulic acid on the performance of soy protein isolate-based edible coatings applied to fresh-cut apples. LWT., 80, 409-415.
 [15] Schmidt, U. S., Pietsch, V. L., Rentschler, C., Kurz, T., Endreß, H. U., & Schuchmann, H. P. (2016). Influence of the degree of esterification on the emulsifying performance of conjugates formed between whey protein isolate and citrus pectin. Food Hydrocoll., 56, 1-8.
[16] Akbari, E., Gholami, M., & Ghobadi, S. (2019). Effect of Pomegranate, Grape and Kiwifruit Juice and Extract on Postharvest Quality of Intact Pear Fruits. JCPP., 9, 139-153.
[17] Laemmli, U. K. (1970). Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature., 227, 680.
[18] Pirestani, S., Nasirpour, A., Keramat, J., Desobry, S., & Jasniewski, J. (2018). Structural properties of canola protein isolate-gum Arabic Maillard conjugate in an aqueous model system. Food Hydrocoll., 79, 228-234.
[19] Mohammadi, A., & Arabshahi, S. (2016). Evaluation of active components and antioxidant activity of essential oil of Boswellia serrata. Food Sci. Technol., 14, 107-117.
[20] Šamec, D., Piljac-Žegarac, J., Bogović, M., Habjanič, K., & Grúz, J. (2011). Antioxidant potency of white (Brassica oleracea L. var. capitata) and Chinese (Brassica rapa L. var. pekinensis (Lour.)) cabbage: The influence of development stage, cultivar choice and seed selection. Sci. Hortic., 128, 78-83.‏
[21] Wu, H-C., Chen, H-M., & Shiau, C-Y. (2003). Free amino acids and peptides as related to antioxidant properties in protein hydrolysates of mackerel (Scomber austriasicus). Int. Food Res. J., 36, 949-57.
[22] Prieto, P., Pineda, M., & Aguilar, M. (1999). Spectrophotometric quantitation of antioxidant capacity through the formation of a phosphomolybdenum complex: specific application to the determination of vitamin E. Anal Biochem ., 269, 337–41.
[23] Sariciban, C., & Yilmaz, T.M. (2010). Modelling the effect of procesing factors on the changes on Cokorparameters of cooked meatballs using response surface methodogy. World Appl. Sci. J., 9, 14-22.
[24] Watts, B. M., Ylimaki, G. L., Jeffery, L. E., & Elias, L. G. (1989). Basic sensory methods for food evaluation. IDRC, Ottawa, ON, CA.
[25] Chance, B., & Maehly, A.C. (1955). Assay of catalases and peroxidases. Methods Enzymol., 2,764-775.
[26] Yingsanga, P., Srilaong, V., Kanlayanarat, S., Noichinda, S., & McGlasson, W. B. (2008). Relationship between browning and related enzymes (PAL, PPO and POD) in rambutan fruit (Nephelium lappaceum Linn.) cvs. Rongrien and See-Chompoo. Postharvest Biol. Technol., 50, 164-168.‏
[27] Djekic, I., Tomic, N., Bourdoux, S., Spilimbergo, S., Smigic, N., Udovicki, B., Hofland, G., Devlieghere, F., & Rajkovic, A. (2018). Comparison of three types of drying (supercritical CO2, air and freeze) on the quality of dried apple–Quality index approach. LWT., 94, 64-72.‏
[28] ISTISAN (1996). Metodi di analisi utilizzati per il controllo chimico degli alimenti, 265. ISTISAN 96/34.
[29] Velickova, E., Winkelhausen., E., Kuzmanova, S., Alves, V.D.,  & Moldao-Martins, M. (2013). Impact of chitosan-bees wax edible coatings on the quality of fresh strawberries (Fragaria ananassa cv. Camarosa) under commercial storage conditions. Food Sci. Technol., 52, 80- 92.
[30] Sadeghi, S., Madadlou, A., & Yarmand, M. (2014). Microemulsification–cold gelation of whey proteins for nanoencapsulation of date palm pit extract. Food Hydrocoll., 35, 590-596.
[31] Zhu, X., Jia, C., Meng, X., Xing, M., Yi, Y., & Gao, X. (2018). Synthesis, characterization of inulin propionate ester, and evaluation of its in vitro effect on SCFA production. StarchStärke., 70, 1800037.
[32] Dong, X., Du, S., Deng, Q., Tang, H., Yang, C., Wei, F., Chen, H., Quek, S. Y., Zhou, A., & Liu, L. (2020). Study on the antioxidant activity and emulsifying properties of flaxseed gum-whey protein isolate conjugates prepared by Maillard reaction. Int. J. Biol. Macromol., 153, 1157-1164.
[33] Martins, J. T., Cerqueira, M. A., Bourbon, A. I., Pinheiro, A. C., Souza, B. W., & Vicente, A. A. (2012). Synergistic effects between κ-carrageenan and locust bean gum on physicochemical properties of edible films made thereof. Food Hydrocoll., 29, 280-289.
[34] Shoaib, M., Shehzad, A., Omar, M., Rakha, A., Raza, H., Sharif, H. R., Shakeel, A., Ansari, A., & Niazi, S. (2016). Inulin: Properties, health benefits and food applications. Carbohydr. Polym., 147, 444-454.
[35] Bryant, C. M., & McClements, D. J. (2000). Influence of sucrose on NaCl-induced gelation of heat denatured whey protein solutions. Int. Food Res. J., 33, 649-653.
[36] Li, X., Wu, X., Bi, J., Liu, X., Li, X., & Guo, C. (2019). Polyphenols accumulation effects on surface color variation in apple slices hot air drying process. LWT., 108, 421-428.
[37] Sharma, S., & Rao, T. R. (2015). Xanthan gum based edible coating enriched with cinnamic acid prevents browning and extends the shelf-life of fresh-cut pears. LWT., 62, 791-800.‏
[38] Tantratian, S., Balmuang, N., & Krusong, W. (2019). Phenolic enrichment of Ma-Kieng seed extract using absorbent and this enriched extract application for safety control of fresh-cut cantaloupe. LWT., 106, 105-112.‏
[39] Kou, X., Li, Y., Wu, J., Chen, Q., & Xue, Z. (2017). Effects of edible coatings on quality and antioxidant activity of Zizyphus Jujuba Miller cv. Dongzao during storage. Transactions of Tianjin University, 23, 51-61.‏
 [40] Tao, Y., Zhang, J., Jiang, S., Xu, Y., Show, P.L., Han, Y., Ye, X. & Ye, M. (2018). Contacting ultrasound enhanced hot-air convective drying of garlic slices: Mass transfer modeling and quality evaluation. J. Food Eng., 235, 79-88.
 [41] Moon, K. M., Lee, B., Cho, W. K., Lee, B. S., Kim, C. Y., & Ma, J. Y. (2018). Swertiajaponin as an anti-browning and antioxidant flavonoid. Food chem., 252, 207-214.‏
[42] Kim, J. S., & Lee, Y. S. (2009). Study of Maillard reaction products derived from aqueous model systems with different peptide chain lengths. Food Chem.,116,846–853.
[43] Lertittikul, W., Benjakul, S., & Tanaka, M. (2007). Characteristics and antioxidative activity of Maillard reaction products from a porcine plasma protein–glucose model system as influenced by pH. Food Chem., 100: 669-677.
[44] Wang, D., Dai, J., Ju, H., Xie, L., Xiao, H., Liu, Y., & Gao, Z. (2015). Drying kinetics of American ginseng slices in thin-layer air impingement dryer. Int. J. Food Eng., 11, 701–771.
[45] Mustapha, A. T., Zhou, C., Sun, Y., Wahia, H., Sarpong, F., Owusu- Ansah, P., & Ma, H. (2019). Simultaneous multifrequency: A possible alternative to improve the efficacy of ultrasound treatment on cherry tomato during storage. J. Food Process. Preserv., 43, 1–16.
[46] Tinello, F., Mihaylova, D., & Lante, A. (2018). Effect of dipping pre-treatment with unripe grape juice on dried “Golden Delicious” apple slices. Food Bioproc Tech., 11, 2275-2285.‏
[47] Jiang, Z., & Brodkorb, A. (2012). Structure and antioxidant activity of Maillard reaction products from α-lactalbumin and β-lactoglobulin with ribose in an aqueous model system. Food Chem.,133,960-968.
[48] Bobinaitė, R., Viskelis, P., Bobinas, Č., Mieželienė, A., Alenčikienė, G., & Venskutonis, P. R. (2016). Raspberry marc extracts increase antioxidative potential, ellagic acid, ellagitannin and anthocyanin concentrations in fruit purees. LWT., 66, 460-467.
[49] Vildan, E., İsmail, T., & Selman, T. (2020). The effect of edible coatings on physical and chemical characteristics of fruit bars. J. Food Meas. Charact., 14, 1775-1783.‏
 [50] Chaijan, S., Panpipat, W., Panya, A., Cheong, L. Z., & Chaijan, M. (2020). Preservation of chilled Asian sea bass (Lates calcarifer) steak by whey protein isolate coating containing polyphenol extract from ginger, lemongrass, or green tea. Food Control., 118, 107400.‏