SENSORY EVALUATION OF KUNU DRINKS PRODUCED FROM POTATO TUBER WITH DIFFERENT SPICES

ABSTRACT
This study determines the effect of crude spice extracts on the quality and consumer acceptability of non-alcoholic beverage produced from sweet potato. Sweet potato tubers were processed into non-alcoholic beverages with different formulations. Sample GGS was treated with 1% ginger extract, sample GRS was treated with 1% garlic extract, sample APS was treated with 1% alligator pepper extract, sample AGS was treated with 0.5% each of ginger and garlic extracts, and sample GAS was treated with 0.5% each of garlic and alligator pepper extracts while sample CCS which serves as control was not treated with any spice extract. Chemical and macromineral composition, Microbiological quality and consumer acceptability were evaluated. Results of chemical analysis indicated pH ranging from 4.40-5.80 and titratate acidity ranged from 0.82-1.42% citric acid. Significant difference (P>0.05) existed in the total solid while no significant difference (P<0.05) existed in the specific gravity of the beverage. The beverage samples were relatively low in vitamin C while vitamin A was high with values ranging from 12.04-12.42 µg/100g with sample GRS having the highest value. Result of macro mineral analysis indicated that addition of crude spice extracts significantly increase calcium, magnesium, sodium, potassium and iron contents of the beverage. Microbiological analysis of the beverage showed absent of conform bacteria while the total viable courts were within acceptable limit as specified by regulatory agencies. Sensory evaluation indicated significant difference (P<0.05) between the samples formulated with spices and the control. Beverage samples formulated with ginger (GGS) and alligator pepper (APS) were preferred. BACKGROUND OF THE STUDY For many years, the Nigerian soft drink industry has been heavily dependent on imported raw materials. In order to conserve foreign exchange, emphasis is now on the development of indigenous beverages and the country's attention has begun to shift toward the local sourcing of raw materials for economic development (Obadina et al., 2008). Kunu-zaki is an indigenous fermented beverage made from unsprouted cereal grains (Adeyemi and Umar 1994). The drink has its origin in the northern parts of Nigeria but is now popular in almost all the states in Nigeria (Gaffa and Ayo 2002). Cereal grains form a major source of dietary nutrients for all people, particularly those in the developing countries (Slavin 2010). However, the nutritional quality of cereal grains and sensory properties of their products are inferior due to lower protein content, deficiency of certain essential amino acids, lower protein and starch availabilities, presence of certain antinutrients, and the coarse nature of the grains (Kahlon 2009). Germination of cereal seeds has been reported as an effective processing treatment to improve the nutritional quality of cereals (Amadou et al., 2011). Sprouting of grains for a limited period causes increased activities of hydrolytic enzymes, improvement in the contents of certain essential amino acids, total sugars, and B-group vitamins, and a decrease in dry matter, starch, and antinutrients (Akinhanmi et al., 2008). The digestibility of storage proteins and starch is improved due to their partial hydrolysis during sprouting (Inyang and Zakari 2008). The magnitude of the nutritional improvement is, however, influenced by the type of cereal, seed quality, and sprouting conditions (Kahlon 2009). The consumption of sprouted cereals is gradually becoming popular in various parts of the world (Slavin 2010). Kunu-zaki (sweet kunu) is a cheap traditional nonalcoholic fermented beverage widely consumed especially during the dry season (Adeyemi and Umar 1994). Kunu-zaki processing is mostly done by women using simple household equipment and utensils. Depending on cereal availability, the unsprouted cereal grains used for kunu-zaki processing are sorghum, maize, millet, guinea corn, or rice in mostly noncomposite proportions. Even though kunu-zaki is popular and fast becoming a household technology in the country, the cereal grains used are selected randomly and diversely. For instance, some women use millet only or sorghum only, while others use only maize. Some also use sorghum with rice, while others use millet with sorghum. The most popular cereals used are sorghum and millet. When kunu-zaki is made from sorghum, the final product is a light-brown liquid. When made from millet, the resulting liquid product is milky white. Investigative studies on comparative sensory properties or consumer preferences of the drink when produced from these different grains are nonexistent. Furthermore, few scientists (Nzelibe et al. 2000; Daramola et al. 2008; Inyang and Zakari 2008) have investigated the effect of some selected malted cereals on properties of kunu-zaki but the sensory properties of each resulting drink were examined only in isolation. Studies have not yet been conducted to compare either the sensory properties and determine the overall acceptability of kunu-zaki when made from sprouted composite cereals, unsprouted composite cereals, composite cereal mixes, or noncomposite cereal proportions. Kunu-zaki is not conventionally produced using sprouted cereals and acha is not a cereal commonly used in kunu-zaki production in spite of its established nutritional advantage. This study therefore sought to compare the sensory properties, the resulting proximate composition, and overall consumer acceptability of kunu-zaki when produced from sprouted and unsprouted cereals in either composite or noncomposite proportions.