Physicochemical, biochemical and nutritional characterization of 'batuan' [Garcinia binucao (Blco.) Choisy] fruit

'Batuan' [Garcinia binucao (Blco.) Choisy], an indigenous, lesser known member of the Guttiferae family with promising export potential is understand and underutilized. Using standard methods, chemical composition, physicochemical properties, antioxidant content and activities, nutritional and sensory quality of the fruits grown in the Visayas State University, Leyte were determined to validate its use as a safe food ingredient and for potential product development. Proximate composition, mineral content, physicochemical properties varied with respect to parts and stages of fruit maturity. Seeds have high content of oil (54.72 +- 0.34% dry basis), tannin, total polyphenols and antioxidant activities but low in proteins. Pulp and the immature fruit were the most acidic. Citric acid was the most abundant organic acid. Analyses of the physicochemical properties revealed that the seed oil was edible of good quality. Lipids of the seed oil were composed of triglycerides and diglycerides as the major acylglycerols, while the unsaponifiable matter was abundant in phytosterols, squalene, beta-carotene and minor amount of alpha-tocopherol, beta-tocopherol as well as vitamin A palmiate. Oleic, stearic, and palmitic acids were the major fatty acids while linoleic, linolenic and arachidic acids constitute the minor components. Osborne fractionation showed globulins and glutelins as the major seed proteins. SDS-PAGE resolved the globulins and glutelins into three groups of polypeptides with molecular weights of about 20-54 kDa. Amino acids analysis revealed that seed proteins contained all the essential amino acids with leucine as the most abundant while trytophan, the most deficient. 'Batuan' seed proteins were mostly made up of acidic and hydrophobic amino acids with glutamic acids (2.67%) as the most abundant. Nutritional assessment including E/T (38.4%), amino acid score (1.6%), predicted PER (3.2-3.7) and BV (98.3%) suggested that the seed proteins are of good quality. Microbial analysis showed that powdered 'batuan' fruits to be safe for human consumption and have comparable acceptability with that of fresh 'batuan' fruits as souring agent in fish stew. Thus, the dry, powder 'batuan' fruits are potential ready-to-use souring agent for domestic consumption, food industry and other applications.