Proximate Composition, Mineral Bioavailability and Functional Properties of Defatted and Undefatted Avocado Pear (Persia americana) Seed Flours

Abstract

The aim of this study was to investigate the proximate composition, mineral bioavailability and functional properties of defatted and undefatted avocado pear seed flours. Avocado pear seed was processed into flour and thereafter defatted using n-hexane. The proximate composition, total and extractable minerals and functional properties of the seed flours were determined using standard methods. Proximate analysis revealed that the defatted seed flour contained significantly (p<0.05) higher protein (11.90%) and ash (2.60%) than the undefatted sample (7.24% and 2.12%, respectively). The undefatted seed flour recorded higher values of moisture (4.84%), fat (3.28%), crude fibre (7.99%), carbohydrate (74.71%) and energy (406.08 kcal) than the defatted sample. Mineral composition of the seed flours also showed that undefatted sample contained significantly (p<0.05) higher contents of sodium (24.56 mg/100 g) and iron (9.05 mg/100 g) than the defatted while defatted sample was significantly (p<0.05) higher in potassium (103.15 mg/100 g), phosphorus (7.80 mg/100 g) and calcium (56.50 mg/100 g). Defatted seed flour gave the highest bioavailable sodium (53.88%), potassium (51.69%), iron (26.07%), phosphorus (47.12%) and calcium (43.47%) while undefatted seed flour had the lowest bioavailable sodium (51.41%), potassium (50.49%), iron (17.45%), phosphorus (45.35%) and calcium (36.35%). There were significant differences (p<0.05) among these values. Results of the functional properties of the seed flours showed that the defatted seed flours were high in water and oil absorption capacities (1.87 g/g and 1.87 g/g, respectively), bulk density (0.85 g/ml) and swelling power (6.75 g/g). However, these values were significantly (p<0.05) similar except for bulk density. Least gelation concentration was 4% for both flours while solubilities were 14.57% and 14.63% for defatted and undefatted seed flour, respectively. The result from this study indicates that avocado pear seed flours may be useful in some food formulations. Defatted avocado pear seed is a good source of protein and can be incorporated into existing food products to provide a protein rich diet.