PHYSICOCHEMICAL, AMBIENT STORAGE STABILITY AND SENSORY PROPERTIES OF ZOBO AS AFFECTED BY PROCESSING METHODS

 

 

 

 

The increasing awareness in health and wellbeing has led to corresponding increase in the demand for healthy beverages worldwide (Chukwu et al., 2017). Zobo is a refreshing and nutritious non-alcoholic beverage produced and sold in Nigeria (Ezeigbo et al., 2015). Zobo drinks consists of 2.5 % protein, 8.5 % carbohydrate, 6.5 % fat, 3.0 mg/100g calcium, 1.8 mg/100g phosphorus, 2.4 mg/100g potassium, 0.2 mg/100g copper, 1.5 mg/100g manganese and 1.0 mg/100g vitamin C (Adeniji, 2017). More so, it contains vitamin E, polyphenol acids and flavonoids, mainly anthocyanins (Akujobi1 et al., 2018; Mohammed et al., 2017). Zobo drink possesses antibacterial, anti-oxidant, nephroprotective and antihepatotoxicity, diuretic effect, effects on lipid metabolism (anti-cholesterol), (Ekenam, 2018; Mohammed et al., 2017), anti-diabetic and anti-hypertensive effects, among others (Chukwu and Akaninwor, 2017; Ezekiel, 2016). The consumption of zobo drink is popular because of its claimed health benefits (Chukwu et al., 2017; Ezekiel, 2016). It is consumed by different classes of people irrespective of socio economic status (Ekenam, 2018; Ezekiel, 2016), sex and age in Nigeria especially in the Northern region and other neighboring African countries (Ekenam, 2018).

Zobo is still locally prepared through indigenous technology and has become accepted in most social gatherings because of its affordability, nutritional value and attractiveness to many people as compared to carbonated drinks (Chukwu et al., 2017; Ezekiel, 2016). It is prepared in several ways using different ingredients, the dried calyces being the major ingredient for preparing the drink (Mohammed et al., 2017). All the methods result into the drink but with a little different taste, depending on the sweeteners and spices used (Mohammed et al., 2017). There are two main techniques of preparing zobo drinks: the steeping and boiling techniques (Salami and Afolayan, 2020). Generally, the steeping technique is carried out by pouring boiled water into clean calyces inside a bowl and set aside for two to four hours. The juice is then separated from the calyces using sieve; fruit juice and sweeteners are then added based on preference whereas the boiling method is carried out by putting clean calyces with sliced fruits pineapple, oranges, and lime (with peel) (based on individuals) into a clean pot, covered with water, and boiled for five minutes, and then the desired spices such as cinnamon, garlic, and ginger are added. More water is added to the content and then left to boil for 30 minutes (Salami and Afolayan, 2020). The juice is then collected from the content using sieve and sweeteners added if desired. 

Techniques of storing food products varies with the nature of the food. For centuries, various storage method were adopted with the purpose of storing food product with minimum costs and optimal, retention of quality (Hu and Jacobsen, 2016). Understanding the best storage condition suitable for a particular food product is of immense significance (Hu and Jacobsen, 2016), as it influences its acceptability and market value, as well as enhancing storage stability (Almeida et al., 2017).  

The acceptance of food products entirely depends on whether it corresponds to consumer expectations and needs (Ekenam, 2018; Chukwu and Akaninwor, 2017). The process through which an individual accepts or rejects food is considered to be of a multi-dimensional nature (Ekenam, 2018). The structure of food acceptability is both variable and dynamic among individuals in different groups and the same individuals I n different time periods and contexts (Maina, 2018). Food acceptability directly relates to the interaction it has with the consumer at a given moment in time. The key factors that determine food acceptability are the sensory characteristics of food since consumers seek foods with specific sensory attributes (Maina, 2018).

Despite the obvious advantages of zobo drinks, their producers are battling with the proper processing technique and best storage method that will enhance its shelf-life considering that it deteriorates quickly after preparation, a condition which may be attributed many factors such as contamination from the sorrel calyces, ingredients and poor quality water used for production, lack of personal hygiene of the producers resulting to microbial activities and growth, and gross inadequate electricity supply in Nigeria. Zobo drinks are commonly hawked in market places, schools, churches, hospitals, motor parks and other public places by low income earners who are not acquainted in food safety measures. The hawkers mostly produce this drink in environment with poor sanitary condition and also package the drink in already used plastic bottles which are inadequately sterilized and could predispose zobo consumers to pathogens of public health importance and as well adversely affect its storage stability. Besides, there is still limited data on the effect of processing techniques and storage on quality acceptability of zobo.

Zobo is a popular indigenous drink consumed by different classes of people irrespective of socio economic status. Evaluating the effect of processing techniques and storage on its quality properties and consumer’s acceptability is a cost-effective means of revealing the appropriate processing technique that is more stable to storage, retained more of the quality attributes of zobo, and as well more acceptable to consumers. Such method will be of immense importance to small scale and industrial zobo processing companies, as well as zobo consumers. Outcome of this research will be of great benefit to researchers. 

 

The main objective of the study was to evaluate the sensory, physico-chemical and ambient storage stability of zobo as affected by processing methods. 

The specific objectives were to: