44C-7 |
Guava seed protein isolate: functional and nutritional characterization |
G. DÁVILA-ORTÍZ1, A. Bernardino-Nicanor1, A. Ortíz-Moreno1, and A. L. Martínez-Ayala2. (1) Dept. Graduados e Investigación en Alimentos, Escuela Nacional de Ciencias Biológicas - IPN, Prolongación de Carpio y Plan de Ayala, Colonia Casco de Santo Tomas, México, DF, 06470, Mexico, (2) Dept. de Biotecnología, Centro de Desarrollo de Productos Bióticos, Kilometro 8.5 Carretera Yautepec-Jojutla, Yautepec-Morelos, 62730, Mexico Currently, studies focused on the use of waste products generated by the food industry indicated they are an alternative source of oils and protein pastes. Examples of such products are tomato, sesame and guava seeds . Two of the biggest processors of guava in Mexico discard about 120 ton/year of this material.The guava seeds are 6 to 12% of the fruit weight. Their proximate composition : 7.6 % protein, 16.0 % fat, 61.4% raw fiber, 0.93% ash and 4.1% water (w/w). The objectives of this work were to determine the biochemical and nutritional properties of the guava seed cultivated in Mexico, as well as to obtain protein isolates by isoelectric precipitation, then characterize some of their functional and nutritional properties. Proximal Analysis (AOAC 1995), protein isolate and isoelectric point (Liadakis et al., 1995), analysis of amino acids (Elkin and Wazynozuk 1987), analysis of tryptophan (Spies and Chambers 1949), "in vitro" Digestibility (Hsu et al., 1977), solubility, emulsifying capacity and emulsion stability (Wang and Kinsella 1976), absorption of fat and water, foaming capacity and foam stability (Kabirullah and Wills 1982), A protein isolate from the guava seed meal was obtained by use of isoelectric precipitation, with 78% extraction yield and 96.7 % protein content of product. Solubility of the isolate was minimum at pH from 4 to 6. Emulsifying capacity and stability of the emulsion was maximum at pH 8. However, the water and oil absorption capacity, as well as the foaming capacity and foam stability, were relatively low. The essencial amino acid profile of the guava seed protein isolate, except for lysine content, is above the values proposed in the FAO/WHO pattern for adults. Its in-vitro protein digestibility was higher than for soybean isolate. These results suggest that the isolate guava seed it is a good source of protein.
Session 44C, Fruit & Vegetable Products: Chemistry
|