Development and process optimization for batuan [Garcinia binucao (Blanco) Choisy] fruit concentrate as souring agent

The study aimed to develop and optimize the processing parameters of batuan fruit concentrate as souring agent using Response Surface Methodology (RSM). The physico-chemical properties (total soluble solids, titratable acidity, and pH) of the 15 treatments of batuan concentrate used as the dependent variable in optimizing the processing parameters namely, time (90-150 minutes); temperature (55-75 deg C); and fruit:water extraction ratio (40:60, 50:50, and 60:40) known as independent variables were studied. The Box-Behnken Design (BBD) of RSM was applied for the optimization process. Likewise, sensory evaluation was performed for the 15 treatments. The observed optimum solution of batuan concentrate underwent proximate analysis, real-time shelf life testing, and simple production cost analysis. Results showed that by applying the RSM-BBD, the optimum solution of batuan concentrate was at time of 150 min, temperature of 75 deg C, and fruit:water extraction ratio of 60:40. Based on the general acceptability score of 7.24, T3 (time, 150 min; temperature, 75°C; and fruit:water extraction ratio, 50:50) was the most preferred. In general, as the time, temperature, and fruit water extraction ratio increases, the TSS and TA also increases. The predicted optimum solution for batuan concentrate using sensory results was at time of 150 min, temperature of 75 deg C, and fruit:water extraction ratio of 60:40, which was in agreement with the optimum solution using physico-chemical results. Concentration process of batuan effects the proximate composition of the sample. A decreasing trend was noted in moisture content of batuan pulp and concentrate (91.52% and 80.03%, respectively). On the other hand, an increasing trend was observed for crude protein content from 0.49% of pulp to 0.82% of concentrate. Likewise, the crude fiber and nitrogen free extract (NFE) also increases for pulp (0.78% and 6.67%, respectively) and concentrate (2.43% and 16.03% respectively). However, there is no significant change (P0.05) observed for ash and crude fat content. The total plate count (10 CFU/g), yeast and mold count (10 CFU/g), and coliform count (3.0 MPN/g) were stable from week 0 to week 12. Also, sensory properties does not indicate considerable change until week 12 showing that batuan concentrate can be stored for at least 12 weeks at ambient temperature. The cost of 200 grams batuan concentrate was found to be P42.90 or approx P43.00.