Effects of Microwave Heating on Sensory Characteristics of Kiwifruit Puree

The effect of microwave processing on the characteristics of kiwifruit puree was evaluated by applying various gentle treatments. Different combinations of microwave power/processing time were applied, with power among 200-1,000 W and time among 60-340 s, and various sensory and instrumental measurements were performed with the aim of establishing correlations and determining which instrumental parameters were the most appropriate to control the quality of kiwi puree. The water and soluble solids of the product, 83 and 14/100 g sample, respectively, did not change due to treatments. For sensory assessment, an expert panel was previously trained to describe the product. Fourteen descriptors were defined, but only the descriptors 'typical kiwifruit colour', 'tone', 'lightness', 'visual consistency' and 'typical taste' were significant to distinguish between kiwifruit puree samples. The instrumental analysis of samples consisted in measuring consistency, viscosity, colour and physicochemical characteristics of the treated and fresh puree. Applying intense treatments (600 W-340 s, 900 W-300 s and 1,000 W-200 s) through high power or long treatment periods or a combination of these factors, mainly affects the consistency (flow distance decreased from 5. 9 to 3. 4 mm/g sample), viscosity (increased from 1. 6 to 2. 5 Pa/s), colour (maximun ¿E was 6 U) and taste of the product. As a result, samples were thicker and with an atypical flavour and kiwifruit colour due to increased clarity (L* increased from 38 to 43) and slight changes in the yellow-green hue (h* decreased from 95 to 94). For the instrumental determinations of colour and visual perception of consistency, the most suitable parameters for quality control are the colour coordinates L*, a*, h*, whiteness index and flow distance measured with a Bostwick consistometer. © 2011 Springer Science+Business Media, LLC.The authors thank the Ministerio de Educacion y Ciencia for the financial support given throughout the Project AGL 2010-22176. The authors are indebted to the Generalitat Valenciana (Valencia, Spain) for the Grant awarded to the author Maria Benlloch. The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.Benlloch Tinoco, M.; Varela Tomasco, PA.; Salvador Alcaraz, A.; Martínez Navarrete, N. (2012). Effects of Microwave Heating on Sensory Characteristics of Kiwifruit Puree. Food and Bioprocess Technology. 5(8):3021-3031. https://doi.org/10.1007/s11947-011-0652-1S3021303158Albert, A., Varela, P., Salvador, A., & Fiszman, S. M. (2009). Improvement of crunchiness of battered fish nuggets. European Food Research and Technology, 228, 923–930.Alegria, P., Pinheiro, J., Gonçalves, E. M., Fernandes, I., Moldao, M., & Abreu, M. (2010). Evaluation of a pre-cut heat treatment as an alternative to chlorine in minimally processed shredded carrot. Innovative Food Science and Emerging Technologies, 11, 155–161.AOAC. (2000). Official Methods of Analysis of AOAC International. Gaithersburg: AOAC.Barboni, T., Cannac, M., & Chiaramonti, N. (2010). Effect of cold storage and ozone treatment on physicochemical parameters, soluble sugars and organic acids in Actinidia deliciosa. Food Chemistry, 121, 946–951.Beirão-da-Costa, S., Steiner, A., Correia, L., Empis, J., & Moldão-Martins, M. (2006). Effects of maturity stage and mild heat treatments on quality of minimally processed kiwifruitfruit. Journal of Food Engineering, 76, 616–625.Bodart, M., de Peñaranda, R., Deneyer, A., & Flamant, G. (2008). Photometry and colorimetry characterisation of materials in daylighting evaluation tools. Building and Environment, 43, 2046–2058.Bourne, M. C. (1982). Food texture and viscosity-concept and measurement. New York: Academic.Cano, M. P., Hernández, A., & de Ancos, B. (1997). High pressure and temperature effects on enzyme inactivation in strawberry and orange products. Journal of Food Science, 62(1), 85–88.Chiralt, A., Martínez-Navarrete, N., Camacho, M. M., & González, C. (1998). Experimentos de fisicoquímica de alimentos. Valencia: Editorial Universidad Politécnica de Valencia (Chapter 3).Chiralt, A., Martínez-Navarrete, N., González, C., Talens, P., & Moraga, G. (2007). Propiedades físicas de los alimentos. Valencia: Editorial Universidad Politécnica de Valencia (Chapter 16).Contreras, C., Martín, M. E., Martínez-Navarrete, N., & Chiralt, A. (2005). Effect of vacuum impregnation and microwave application on structural changes occurred during air drying of apple. Food Science and Technology/LWT, 38(5), 471–477.Contreras, C., Martín-Esparza, M. E., Martínez-Navarrete, N., & Chiralt, A. (2007). Influence of osmotic pre-treatment and microwave application on properties of air dried strawberry related to structural changes. European Food Research and Technology, 224, 499–504.de Ancos, B., Cano, M. P., Hernández, A., & Monreal, M. (1999). Effects of microwave heating on pigment composition and color of fruit purees. Journal of the Science of Food and Agriculture, 79, 663–670.Dubost, N. J., Shewfelt, R. L., & Eitenmiller, R. R. (2003). Consumer acceptability, sensory and instrumental analysis of peanut soy spreads. Journal of Food Quality, 26, 27–42.Escribano, S., Sánchez, F. J., & Lázaro, A. (2010). Establishment of a sensory characterization protocol for melon (Cucumis melo L.) and its correlation with physical-chemical attributes: indications for future genetics improvements. European Food Research and Technology, 231, 611–621.Fang, L., Jiang, B., & Zhang, T. (2008). Effect of combined high pressure and thermal treatment in kiwifruit peroxidase. Food Chemistry, 109, 802–807.Fisk, C. L., McDaniel, M. R., Strick, B. C., & Zhao, Y. (2006). Physicochemical, sensory, and nutritive qualities of hardy kiwifruit (Actinidia arguta ‘Ananasnaya’) as affected by harvest maturity and storage. Sensory and Nutritive Qualities of Food, 71(3), 204–210.Fúster, C., Préstamo, G., & Cano, M. P. (1994). Drip loss, peroxidase and sensory changes in kiwi fruit slices during frozen storage. Journal of the Science of Food and Agriculture, 64, 23–29.Guldas, M. (2003). Peeling and the physical and chemical properties of kiwi fruit. Journal of Food Processing Preservation, 27, 271–284.Igual, M., Contreras, C., & Martínez-Navarrete, N. (2010). Non-conventional techniques to obtain grapefruit jam. Innovative Food Science and Emerging Technologies, 11, 335–341.Igual, M., García-Martínez, E., Camacho, M. M., & Martínez-Navarrete, N. (2010). Effect of thermal treatment and storage on the stability of organic acids and the functional value of grapefruit juice. Food Chemistry, 118, 291–299.Jaeger, S. R., Rossiter, K. L., Wismer, W. V., & Harker, F. R. (2003). Consumer-driven product development in the kiwifruit industry. Food Quality and Preference, 14, 187–198.Lawless, H., & Heymann, H. (1998). Sensory evaluation of food: Principles and practices. New York: Chapman & Hall.MAPA (2010). Plataforma de conocimiento para el medio rural y pesquero. National Agricultural Statistics Database, Spain, Available at: www.mapa.es . Accessed 05 October 2010.Maskan, M. (2001). Kinetics of colour change of kiwifruits during hot air and microwave drying. Journal of Food Engineering, 48, 169–175.Mohammadi, A., Rafiee, S., Emam-Djomeh, Z., & Keyhani, A. (2008). Kinetic models for colour change in kiwifruit slices during Hoy Air drying. World Journal of Agricultural Sciences, 4(3), 376–383.Moretti, C. L., Mattos, L. M., Machado, C. M. M., & Kluge, R. A. (2007). Physiological and quality attributes associated with different centrifugation times of baby carrots. Horticultura Brasileira, 25, 557–561.Nielsen, S. S. (2010). Food analysis laboratory manual. New York: Springer.Oraguzie, N., Alspach, P., Volz, R., Whitworz, C., Ranatunga, C., Weskett, R., et al. (2009). Postharvest assessment of fruit quality parameters in apple using both instrument and an expert panel. Posthaverst Biology and Technology., 52, 279–287.Pagliarini, E., Laureati, M., & Lavelli, V. (2010). Sensory evaluation of gluten-free breads assessed by a trained panel of celiac assessors. European Food Research and Technology, 231, 37–46.Park, E. Y., & Luh, B. S. (1985). Polyphenol oxidase of kiwifruit. Journal of Food Science, 50, 678–684.Schubert, H., & Regier, M. (2010). The microwave processing of foods. London: Woodhead.Segnini, S., Dejmek, P., & Öste, R. (1999). Relationship between instrumental and sensory analysis of texture and colour of potato chips. Journal of Texture Studies, 30, 677–690.Sinija, V. R., & Mishra, H. N. (2011). Fuzzy analysis of sensory data for quality evaluation and ranking of instant green Tea powder and granules. Food Bioprocess Technology, 4, 408–416.Soufleros, E. H., Pissa, I., Petridis, D., Lygerakis, M., Mermelas, K., Boukouvalas, G., et al. (2001). Instrumental analysis of volatile and other compounds of Greek kiwi wine; sensory evaluation and optimization of its composition. Analytical, Nutritional and Clinical Methods Section, 75, 487–500.Vadivambal, R., & Jayas, D. S. (2007). Changes in quality of microwave-treated agricultural products-a review. Biosystems Engineering, 98, 1–16.Worch, T., Lê, S., & Punter, P. (2010). How reliable are the consumers? Comparison of sensory profiles from consumers and experts. Food Quality and Preference, 21, 309–318.Zanoni, B., Lavelli, V., Ambrosoli, R., Garavaglia, L., Minati, J., & Pagliarini, E. (2007). A model to predict shelf-life in air and darkness of cut, ready-to-use, fresh carrots under both isothermal and non-isothermal conditions. Journal of Food Engineering, 79, 586–591.Zolfaghari, M., Sahari, M. A., Barzegar, M., & Samadloiy, H. (2010). Physicochemical and enzymatic properties of five kiwifruit cultivars during cold storage. Food Bioprocess Technology, 3, 239–246

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