PHYSICOCHEMICAL AND SENSORY PROPERTIES OF MIXED FRUIT JUICE BEVERAGE PRODUCED FROM MIXTURE OF WATERMELON, PINEAPPLE AND APPLE JUICES

PHYSICOCHEMICAL AND SENSORY PROPERTIES OF MIXED FRUIT JUICE PRODUCED FROM MIXTURE OF WATERMELON, PINEAPPLE, AND APPLE JUICES

Abstract: This study was aimed at the use of watermelon (Citrulus lanatus), Pineapple (Ananas cosmosus) and Apple (Malus domesticus) to produce mixed fruit juice.  The fruits were sliced, pulped using an electric blender and filtered separately with a muslin cloth. The individual fruit juices were blended in ratios and pasteurized at 80⁰C for 10 minutes while the standards were not blended the three juices SWJ (100% standard watermelon juice) SPJ (100% Standard pineapple juice) and SAJ (100% standard apple juice). The physicochemical and sensory properties of the three standards (watermelon, Pineapple, and Apple) and their blends were carried out. The pH, total sugar content (⁰Brix), titratable acidity, ascorbic acid content and total soluble solids of the fruit juices were studied and the results ranged from 3.96 to 4.29; 3.43 to 12.37; 2.47 to 7.62%; 0.84 to 2.29; and 3.40 to 10.33%; respectively. Sensory evaluation results showed that a significant difference existed (p <0.05) in terms of color, taste, flavor, texture and general acceptability of watermelon, pineapple, and apple juice blends when compared to the standard samples. From all the analyses conducted it was observed that the mixed fruit juice blends were accepted by the panelist. Sample 2 (40% pineapple, 15% apple, and 45% watermelon) had the highest acceptability in terms of color and flavor with sample 12 (30% Pineapple, 15% Apple and 55% Watermelon) having the least acceptability. In terms of texture, it was observed that sample 2(40% Pineapple, 15% Apple, 45% Watermelon) had the highest acceptability while the other samples were significantly the same. In general acceptability, sample 2 (40% Pineapple, 15% Apple, and 45% Watermelon) had the highest acceptability. Though the values for pH and Titratable acidity occurred in a reversed case which showed that these juices have the advantages of being stored for a long time, there is a need to carry out further investigation to determine its shelf-life stability.

CHAPTER ONE

1.1 BACKGROUND TO THE STUDY

In our nation, Nigeria, many organizations from both the governmental sectors and non-governmental sectors are actively promoting the processing of fruits and vegetables. Fruits and vegetables are among the most important food of mankind as they are not only nutritive but also indispensable for the maintenance of health (Wong et. al., 2003). They are valued for their appearance, characteristic flavor and taste. They play important roles in the diets of most people in the tropics, providing essential minerals and vitamins and adding color, flavor, and variety of monotonous diet (Ragaert et. al., 2004). Fruits and vegetables are abundant under tropical conditions due to high ambient temperature and humidity, pests and disease infestation, poor handling and storage facilities (Levi et al., 1983). In 1988, World Resources Institute reported that not only are losses clearly a waste of food but they also represent a similar waste of human effort, farm input, livelihood, investment and scarce resources such as water. This implies that fruits, most often, do not attain their maximum market value thereby leading to less return to the grower as an individual and economic loss to the nation as a whole. Processing of fruits and vegetables to juices and other valuable products are the ways abundant fruits and vegetables can be utilized to reduce wastage and bring economic returns to the farmers. However, improvement and methods of processing and preservation of fruits and vegetable production has made it possible for the successful feeding of heavy population in countries unable to raise their own fruits. As a result of the improved methods, the fruits and vegetables which are only edible for a short period of time are now available all year round for human consumption. The fruits generally used in the making of fruit juices are orange, grape, apple, watermelon, pineapple, mango, etc. while some of the fruits are widely consumed fresh. Indigenous tropical fruits, for example, pineapple (Ananas cosmosus) are a tropical plant with edible multiple fruits from the Bromeliaceae family. Pineapple fruit can be consumed fresh, cooked, juiced and preserved (Bartolome et. al., 1994). The fresh pineapple juice is a popular product derived from the pineapple fruit due to its pleasant taste, aroma, flavor and numerous functional properties. It is produced from breaking the fleshy pulp of the pineapple fruit and extracting the juice for consumption. Pineapple juice contains a variety of minerals especially manganese as well as amino acids, various sugars, vitamins, and polyphenols (Hossain et. al., 2015) and considered as a functional fruit beverage due to health-promoting properties.

Watermelon (Citrullus lanatus) is a fruit that belongs to the family of Cucurbitaceae. The fruit normally contains 60% flesh and about 90% of the flesh is juicy which 7-10% (w/v) sugar (Asha et al., 2014). Watermelon juice as a beverage is produced through pressing or breaking up of the fruit and extracting the juices. The juice contained can be consumed with or without sugar or carbon dioxide addition. Watermelon juices are rich sources of lycopene and phenolic antioxidants and are widely consumed around the world for its immune-supportive Vitamin C. It constitutes one of the most important fruit beverages for man and maintains good health by making up for losses in the human diet. According to the US FDA (2001), watermelon juice is typically pasteurized in order to eliminate some bacteria pathogen which can cause a hazardous effect in the health of the consumers.

Apple (Malus domesticus) is a pome that belongs to the family of Roseaceae. It is one of the most widely cultivated tree fruit (Potter et. al,.2007). Apples, compared to many other fruits and vegetables, may have a relatively low amount of Vitamin C but they are very rich sources of other antioxidant compounds (Boyer and Liu, 2004). They are widely consumed fresh or processed into other Apple products such as apple sauce, apple cider, apple jelly, apple juice, and vinegar. The apple juice is a well known and appreciated beverage all over the world not only for its taste and nutritional properties but also for its numerous health effects. Fruit juice blends can be produced from apple and other fruits such as watermelon, pineapple, etc. in order to combine all the basic nutrients in different fruits to give a better quality juice both nutritionally and organoleptically. These fruit juice blends are considered as a functional beverage intended for human consumption due to the important role they play in maintaining the body balance and preventing dehydration.

Due to an increase in the demand for fruit juice and vegetable beverage with the original characteristics of the fresh fruit beverage free from chemical additives in the potential food market, researchers and industrialists has embarked on the development of new technology that are able to improve the processing of these fruit-based beverages in various ways including the effect of thermal processing of the products in order to improve the sensory, microbiological and shelf stability of these beverages (Costescu et. al., 2006).

1.2 AIM AND OBJECTIVES OF THE STUDY

The broad aim of this study is to produce mixed fruit juice combined with partial replacement of watermelon juice with pineapple and apple juice. Watermelon juice forms the bases of the product.

The specific objectives include:

1. To determine the physicochemical properties of the mixed fruit juice samples.
2. To determine the ascorbic acid content of the mixed fruit juice produced.
3. To evaluate the organoleptic properties and general acceptability of the fruit juices produced.

1.3 JUSTIFICATION OF THE STUDY

According to Costescu et.al. (2006), the need to increase the utilization of fruits and vegetables in beverage production has been on increases demand due to their role in solving nutritional problems through exploitation of the nutritional and economic potential of fruits and vegetables. Beverage as a functional food can be produced from varieties of fruits and dairy sources or a combination of them both. Much research has been carried out earlier in this context to determine the effects of different processing techniques on the nutritional components and consumers’ acceptability of such beverages. Akinosun (2010) has successfully produced juice from blends of watermelon and pineapple fruits at the ratio of 90 to 10% respectively. However, there has not been optimized work on mixing another fruit juice sample in the juice blends. Thus, this present work is designed to address the missing gaps of the previous researchers.

1.4 SIGNIFICANCE OF THE STUDY

Consumer’s demands for healthy and nutritious food products with a fresh-like appearance have undergone a continuous rise during the years. The importance of fruit and vegetables in human nutrition is clearly evident. FAO, (2005) reveals that fruits and vegetable juice play a significant role in human nutrition, especially as sources of Vitamin C, A, thiamine B1, pyridoxine, folacin, minerals, and dietary fiber. Presently, a variety of fruit juice blends has been produced to form a product with improved nutritional and sensory quality. A continuous consumption of these fruit-based products is highly associated with the reduced risk of chronic and degenerative diseases. In this sense, scientists and technologists have been focused on the development of mixture methodology for quality evaluation of mixed fruit juices ready to serve beverages (Deka et. al., 2001). The consumption of mixed fruit-based beverages has significantly increased in the last years, becoming one of the food industry sectors with the highest growth worldwide.