Thesis Abstract

Abstract
Instant kunun zaki is a popular ready-to-drink millet-based beverage in Nigeria. This study aimed to evaluate the changes in the physicochemical properties of instant kunun zaki flours produced from millet (Pennisetum typhoiduem) and malts of cowpea (Vigna unguiculata) and soybean (Glycine max) during storage. The flours were prepared using traditional methods and blended into instant kunun zaki. The physicochemical properties, including moisture content, water absorption capacity, bulk density, and pasting properties, were analyzed at the beginning of storage (0 days) and then at 30-day intervals for a total of 120 days. The results indicated that the initial moisture content of the instant kunun zaki flours ranged from 6.92% to 11.35%. During storage, there was a gradual increase in the moisture content of all the samples, with the highest increase observed in the cowpea malt-based flour. The water absorption capacity of the flours also increased over the storage period, with cowpea malt-based flour showing the highest values. Bulk density decreased significantly during storage, indicating changes in the structure of the flours. The pasting properties of the instant kunun zaki flours were analyzed using a Rapid Visco Analyzer (RVA). The peak viscosity, trough, breakdown, final viscosity, and setback values were determined. The results showed that all the samples exhibited differences in their pasting profiles, with cowpea malt-based flour having the highest peak viscosity and final viscosity. During storage, there were fluctuations in the pasting properties, indicating possible changes in the starch structure and composition of the flours. Overall, the physicochemical properties of instant kunun zaki flours produced from millet and malts of cowpea and soybean changed during storage. The increase in moisture content, water absorption capacity, and changes in bulk density and pasting properties suggest possible modifications in the structural and functional properties of the flours. These changes could impact the quality and shelf-life of instant kunun zaki products and should be considered in storage and processing practices to maintain product quality and consumer acceptability.

Thesis Overview

1. INTRODUCTION

       Kunun zaki is a traditional, non-alcoholic and non-carbonated beverage widely  consumed in Northern Nigeria and is becoming popular in the South .It is consumed at any time of the day by both adults and children, as breakfast drink. It an appetizer and it is commonly served at social gatherings. The ingredients used in its manufacture include, millet (Pennisetum typhoideum), sorghum (Sorghum vulgare), maize (Zea mays), rice (Oryza sativa), spices [ginger (Zingiber officinale), garlic (Allium sativum), red peeper (Capsicum annuum), black pepper (Piper nigrum), clove (Syzygium aromaticum)]. Also Cadaba farinosa, potatoes (Ipomea batatas)(Efiuvwevwere and Akoma, 1995). Tiger nuts (Cyperus esculentus) and groundnut (Arachis hypogea) may be added to sweeten and enrich protein content.

Kunun zaki is rich in carbohydrates, vitamins and minerals but it is low in protein (Ayo and Okaka, 1998). Sugar may be added instead of pepper to meet the demands of some consumers (Onuorah et al, 1987; Akoma et al 2006). Some consumers consume kunun zaki without sugar or pepper (Adeyemi and Umar, 1994). Kunun zaki is accepted based on its colour (cream) and flavour (millet mixed with ginger flavour).

Traditionally, kunun zaki is produced by steeping the grains in water, wet milling with spices and sieving, the overall process taking 24 hours (Adeyemi and Umar, 1994). This traditional method has been improved by shortening the processing time to 12 hours by steeping the grains in warm water containing 15% sodium metabisulphate, wet-milling, liquefication and saccharification with enzymes in the grain, filtering, bottling and pasteurization at 80oC for 30 minutes before refrigeration at 4-8 oC (Gaffa and Ayo, 2002). Traditionally produced kunun zaki has a shelf life of about 24 hours (Adeyemi and Umar, 1994) at ambient temperature. The improved method can however extend the shelf life to 8 days after pasteurization followed by refrigeration storage (Osuntogun and Aboada, 2004) which can last for 90 days when chemical preservation is applied as has been achieved by FIIRO, Nigeria (Haard, 1998). Also instant kunun zaki flour has been produced by Dala Foods Limited Kano, Nigeria and commercialized Kunun Tsamiya, the product being made only from millet. Further work was done by Amazikwu (2007) where she produced instant kunun zaki flours from millet-cowpea malt and millet-soybean malt to enhance protein content and sensory quality. She also carried out sensory evaluation and the samples were rated acceptable by consumers.  However no packaging or storage studies have been carried out on the instant powders and shelf life is also largely dependent upon the storage conditions and packaging materials used. This work is therefore a follow up of the work done by Amazikwu (2007). Against this background, this project was designed to produce instant kunun zaki flours from millet-cowpea malt and millet-soybean malt combinations and store in good flexible packaging material. Specific attention was therefore directed at;

(i) producing instant kunun zaki powders from millet-cowpea malt and millet-soybean malt by steam heating.

(ii) studying the changes in physicochemical and functional properties of the packaged flours during storage.