EVALUATION OF THE SHELF-LIFE AND PHYSICOCHEMICAL ATTRIBUTES OF FLOUR BLENDS MADE FROM AFRICAN YAM BEAN (SPHENOSTYLIS STENOCARPA) AND CORN (ZEA MAYS)

Abstract

Background: Storage attributes of food determines its availability and nutritional contribution. Objectives: This 50-week experimental study evaluated the shelf-life and physicochemical characteristics of African yam bean (AYB) and corn flour blends. Methodology: Coffee brown AYB and white corn seeds were processed into flours, and blended in ratios of AYB100%, AYB70%: Corn30%, AYB50%: Corn50%, AYB30%: Corn70%, Corn100% using standard procedures. Their microbial, proximate, pH and titratable acidity were determined fortnightly for 50 weeks. Data collected was analyzed with IBM Statistical Product for Service Solution (SPSS) software version 21 and presented with descriptive statistics (frequencies, percentages, means, standard deviation). Results: AYB100%, AYB70%: Corn30%, AYB50%: Corn50%, AYB30%: Corn70%, and Corn100% had acceptable total viable counts (2.80x104 , 1.9 x101 , 3.2 x101 , 1.0 x101 and 1.1 x101) cfu/g at weeks 42, 36, 38, 38, and 44 respectively. Sample AYB70%: Corn30% exceeded the acceptable limit in mold count (3.10x102) at above 20 weeks of storage. The coliform count acceptability for AYB100% (2.00x101), AYB70%: Corn30% (8.50x101), AYB50%: Corn50% (2.0x101), AYB30%: Corn70%, (1.00x101), and Corn100% (3.90x101) were up to 50, 34, 50, 36, and 42 weeks respectively. The proximate composition, pH and TTA of the flour blends for 50 weeks storage period showed progressive increases in moisture (13.5%), fat (7.6%), crude fiber (8.1%), ash (8.4%) and TTA (0.151%) and decreases in protein (23.7%), carbohydrate (38.85%) and pH (1.89%). Conclusion: The blends maintained acceptable microbial counts and physicochemical properties within 30 weeks of storage, suggesting suitable stability for consumption within this period