Quality evaluation of beer-like low-calorie beverage from local corn (Zea mays L.)

A study was conducted which aimed to evaluate the quality of beer-like, low-calorie beverage from two local corn varieties, waxy (lagkitan) and non-waxy (IPB var 1). Four treatments (with and without saccharification) for the two corn varieties were done to determine the effect of saccharification on the quality of the product. Optimization of pre-fermentation treatments were done for maximum conversion of corn starch to fermentable sugars. Decoction mashing method was applied prior to fermentation. Chemical analyses (pH, TSS [total soluble solids], TTA [total titratable acidity], amino nitrogen(mg-percent), total sugar (percent) and reducing sugars (percent) and alcohol content (percent) were conducted to monitor changes in the fermenting mash at specified time intervals during fermentation. Caloric values and consumers' acceptability of the finished products as to their attributes such as color, clarity, flavor, aroma, after-taste and general acceptability were evaluated. Optimization of pre-fermentation process revealed that optimum steeping time and temperature for waxy corn was 24 hours at 30 deg C (36.03 percent MC) and 72 hours at 30 deg C (35.02 percent MC) for non-waxy corn. Optimum generation time and temperature was 5 days at 30 deg C for waxy (3.88 percent RS [reducing sugar]) and 6 days at 30 deg C for non-waxy corn (4.35 percent RS). Dilution of corn grist to water was found to b e most favorable at 1:4 with a TSS value of 15.20 deg Brix for waxy and 13.80 deg Brix for non-waxy corn. In general, there was an increase in acidity as fermentation time progressed. TSS decreased with fermentation time for all four treatments. However, TSS was found to be higher for saccharified samples (WWS and NWS) during initial and final day of fermentation as compared with WNS and NWNS. This indicates that the former were efficiently degraded by the saccharifying yeast (Saccharomycopsis fibuligera) and molds/Rhizopus oryzae, and Aspergillus awamori); enzymes from these microorganisms are capable of synthesizing alpha-amylase and Beta-amylase that catalyses random breakdown of starch into simple sugars. The percent RS and percent TS decreased with prolonged fermentation time indicating conversion of sugars to alcohol. A lower alcohol (2 percent) content was obtained from the control as compared with both saccharified samples (4 percent). Statistical analysis showed significant differences in the chemical analysis of waxy and non-waxy corn as influenced by saccharification during the fermentation process. Sensory evaluation revealed that in terms of color, no significant effect of saccharification exists among saccharified and waxy and non-waxy corn. Except for saccharified corn, no significant differences in clarity was observed in all samples. However, standing all samples for more than 1 month showed remarkable clarity of the products. For flavor, aroma and after taste, all four treatments were not significantly different from each other. On the other hand, non-waxy corn with saccharification obtained the most favorable mean rating for general acceptability. Thus, saccharified non-waxy corn was found most acceptable among the four treatments and has the highest potential for beer brewing.