Preserving effect of microencapsulated polyphenols from peanut skins on soymilk beverage

LARRAURI MARIANA; ASENSIO CLAUDIA M.; MARTIN MARIA PAULA; GROSSO NELSON R.; NEPOTE VALERIA

Córdoba

Congreso; VI Congreso Internacional de Ciencia y Tecnología de los Alimentos; 2016

Ministerio de Ciencia, Tecnología y Alimentos de la Provincia de Córodba

Soy has a high nutritional value and contains a high percentage of good quality proteins, so it is a good supplement for a diet. Soymilk is one of the most popular soybean products well-known for its health benefits. The addition of antioxidant in soymilk is an alternative to increase its functional properties. Polyphenol compounds are good antioxidant and they can be included in different kind of food matrices to improve their stability. Peanut skin extracts have a high total phenolic content with antioxidant activity and these compounds can be used as natural antioxidants for the food industry. Nowadays, consumers demand new vegetable beverages with functional properties. The objective of this study was to evaluate the antioxidant activity and chemical stability of soymilkbeverages supplemented with microencapsulated polyphenols (natural antioxidants) from peanut skins. Peanut skin crude extract was obtained by solid-liquid extraction from peanut skins using ethanol 70%. Then, it was partitioned in two fractions with ethyl acetate (BEA) and water. The BEA fraction was used to prepared microcapsules. Hydroxypropylmethyl cellulose was the material for microcapsule wall. three soymilk samples were prepared: without antioxidant (SMC), with BEA (SMB), and with BEA microcapsules (SMCPB). Samples were stored during 30 days at 4 °C. Chemical indicators (acidity, hydroperoxides and phenolic content) and antioxidant activity (radical scavenging activity on DPPH) were evaluated on samples every 7 days. Data were analyzed by ANOVA and LSD test. At the end of storage, SMB and SMCPB showed the lowest total titratableacidity (0.043 and 0.044 g lactic acid/kg, respectively) and hydroperoxides (15.27 and 12.36 μeqO2/kg, respectively) with respect to value observed in SMC (acidity: 0.067 g lactic acid/kg, and hydroperoxides: 23.26 μeqO2/kg, respectively). SMB exhibited the highest phenolic content (746.09 mg gallic acid/L) followed by SMCPB (394.36 mg gallic acid/L). The greatest antioxidant activity measured as DPPH radical scavenging activity (54.89% radical scavenging activity) was detected in SMB. Soymilk supplemented with peanut skin extract (BEA) and microcapsules of BEA have higher stability during storage at 4 °C. In addition, higher antioxidant activity present in soymilks supplemented with BEA increase its functional properties as a health food. Soymilk is an alternativeto include natural antioxidants like polyphenol from peanut skins. New Technologies like microencapsulation contribute to a more efficient function of the antioxidant in a food product. The results of this study promote the development of new vegetable beverages with functional properties using natural ingredients.