QUALITY ATTRIBUTES AND STORABILITY OF NOODLES FROM BLEND OF PRO-VITAMIN A CASSAVA (Manihot esculenta CRANTZ) AND AFRICAN YAM BEAN (Sphenostylis stenocarpa HARMS) FLOURS

Abstract

Noodle, a convenient wheat-based food, is high in carbohydrate but low in protein and vitamin contents. Imported wheat is mostly used to meet the demand for convenience foods preparation in Nigeria. Alternative to wheat, Pro-Vitamin A Cassava (PVAC), a good source of vitamin A and African Yam Bean (AYB), rich in protein content, could be used for noodle production. However, information on utilisation of PVAC and AYB flour mixture for preparation of noodle is sparse. This study was designed to investigate quality and storage attributes of noodles prepared from blend of PVAC and AYB flours. From preliminary trials, PVAC (cultivar 07/593) and AYB (accession TSs 94) were separately processed into flours using standard procedures. The flour blend of PVAC (60-90%) and AYB (10-40%) were prepared using mixture experimental design. Protein, β-carotene and fat contents of blend were determined by standard methods and used as criteria to select the desirable blend by maximising protein and β-carotene contents, while minimising fat content. Noodles were produced from the desirable blend (100 g) and process optimised using response surface methodology with moisture content (50-60%) and steaming time (1-4 min) as variables. Protein, β carotene, fat contents, cooking qualities and textural attributes of noodles were analysed using standard methods. Protein quality (protein efficiency, true protein digestibility and feed efficiency) of the noodles was compared with standard diet (casein diet) using male wistar rats. Overall acceptability of cooked noodles was determined using 50 panelists and a commercial noodle as control. Samples were stored in Low Density Polyethylene (LDPE) (100 µm) and High Density Polyethylene (HDPE) (150 µm and 200 µm) at ambient condition (27±2oC, 64±2.00%, RH). Colour, moisture content, β-carotene retention, total viable, mould and yeast counts of stored samples were determined at two week intervals over a six-month duration. Data were analysed using ANOVA at α0.05. Protein, β-carotene and fat contents of flour blend were 2.31-10.52%, 3.5-7.60 µg/g and 0.57-1.40%, respectively, while those of optimised blend (70.49%PVAC and 29.51%AYB) were 6.69%, 6.45 µg/g and 0.58%, respectively. The protein, β carotene, fat contents, cooking yield, cooking loss and cooking time of noodles were 9.25-11.55%, 2.97-4.99 µg/g, 0.88-1.18%, 177.84-209.93%, 6.87-10.80% and 7.20- 9.45 min, respectively. Textural properties varied from 1,165 to 2,382 g, 254.50 to 1,082 g and 18.50 to 68.50 g for hardness, chewiness and stickiness, respectively. Protein efficiency, true protein digestibility and feed efficiency of experimental samples (2.24-2.37%, 95.5-97.00% and 0.15-0.20%, respectively) were not significantly different from that of control (casein diet). Overall acceptability varied significantly with commercial noodle having the highest value followed by sample hydrated and steamed at 50% and 1 min. The best packaging material based on colour, moisture content, β-carotene retention and microbiological qualities of the samples was HDPE (200 µm). Pro-vitamin A cassava-African yam bean noodles of acceptable nutritional, cooking and sensory qualities were produced. High-density polyethylene (200 µm) was suitable for storage of the noodles at tropical ambient condition.