INTRODUCTION Fruit juices are becoming important part of modern diet in many communities. Their consumption is popular in Nigeria because of their health and invigorating benefits (Alaka et al., 2003; Ndife et al., 2013). They act as nutritious beverages and play significant roles in healthy diets because they offer good taste and varieties of nutrients found naturally in fruits (OÕNeil and Nicklas, 2008; Hossain et al., 2012). In Nigeria, different kinds of seasonal fruits are available including apple, orange, pineapple, and grape which provide an abundance of vitamins, minerals, antioxidants and fibers, all of which are essential for human health (Jasmine, 2012). Fruit juice intake is a convenient way by which people receive the benefits of various fruits when whole fruit is not readily available or desired (Nitu et al., 2010). Properly extracted juices are very similar to the fruit; they contain most substances which are found in the original ripe and sound fruit from which the juice is made. Fruit juices are always 100% fruit products and should not be confused with soft drinks or other refreshing drinks (Landon, 2007). They are available either in their freshly prepared form or industrially processed form. In either case, it is expected to be free from contaminants and contain most substances which are found in the original ripe and sound fruit from which the juice is extracted, without added sugar or preservative (Hassan et al., 2014). It should be void of environmental pollutants such as toxic metals which impacts negatively on quality and are deleterious to health. Fruit juices contain water and varying concentrations of carbohydrates such as sucrose, fructose, glucose and sorbitol (Oranusi et al., 2012). They are also rich in phytochemicals, minerals and vitamins which are responsible for the several health benefits associated with their consumption, including reduction in the risk of a variety of chronic diseases such as cardiovascular disease and cancer (Cashwell, 2009). However, the beneficial health effects of fruit juices depends on the amount consumed in a daily diet, type of fruit and the content of biologically active compounds. In recent times, the quality of fruit juices is diminished with increasing concentration of toxic compounds including added sugar, heavy metals and other contaminants. Excessive sugar consumption from fruit juice has been associated with the development of obesity, type II diabetes and dental caries (Cashwell, 2009). The minerals contained in fruit juices including sodium, potassium, magnesium, phosphorus, calcium and iron are essential for good health if present in adequate concentrations (Ofori et al., 2013) and harmful when in excess or deficient, hence the need for their proper representation. 15 16 1.1 Research Terminologies Beverages Beverages are liquids specifically prepared for human consumption, usually excluding water. This may include tea, coffee, liquor, beer, milk, juice or soft drinks. Despite the fact that most beverages including juice, soft drinks and carbonated drinks have some form of water in them, water itself is often not classified as a beverage. Beverages can be categorised as alcoholic and non alcoholic based on the percentage ethanol present. Non alcoholic beverages can further be classified into sweetened beverages and fruit/vegetable juices. A sweetened beverage is any beverage to which a caloric sweetener has been added, including carbonated or non-carbonated soft drinks, fruit punch, fruit drinks, lemonade, sweetened powder drinks, or any other artificially sweetened beverages. Fruit juices on the other hand are not sweetened drinks and should not be categorized as such. They are composed exclusively of an aqueous liquid or liquids extracted from one or more fruits with no added caloric sweeteners (Landon, 2007). Fruit juice A fruit juice is defined as the clear or uniformly cloudy unfermented liquid recovered from sound fruits by pressing and other mechanical means (Nnam and Njoku, 2005). It is a drink consisting of 100% pure fruit juice, which typically contains no preservatives or other added ingredients. It is a fruit product, which could be easily consumed by infants, children and adults to meet their nutrient needs particularly that of micronutrients (Nzeagwu and Onimawo, 2010). Freshly squeezed Juice Freshly squeezed juices are produced by squeezing the juice from the fruit of choice, which is then immediately consumed or packaged and transported to the retailer as the case may be, usually within 24 hours. These juices often do not undergo any form of pasteurization and therefore typically have a very short shelf life usually 2-3 days (Cashwell, 2009). Concentrate This is obtained by the removal of water from fruit juice for the purpose of achieving reduction in weight and volume for easier transportation. At the time of usage, water is added back to the concentrate to reconstitute 100% fruit juice. Juices made from concentrates are available and similar in nutrient to the freshly squeezed juice. During production, fruit juices from concentrate 16 17 are typically heat-treated, to ensure that any unwanted spoilage pathogens, including bacteria or moulds, are destroyed (Cashwell, 2009). Fruit drinks (Juice drinks) Fruit drinks are products which contain anything less than 100% pure fruit juice (Landon, 2007; Cashwell, 2009). The level of fruit juice contained in these drinks can be found in the ingredients panel, usually on the back of the pack. There are a vast range of products with differing percentages of fruit juice. These drinks may include those that are purchased in a ready-to-drink format, or those that require dilution prior to consumption which may include products made with sugar, as well as low sugar options made with sweeteners. Nectars Fruit juice nectars are defined as the fermentable but unfermented product obtained by the addition of water and sugar to fruit juice or concentrated fruit juice. It consists of less than 100%, but more than 20% fruit juice (Cashwell, 2009). The term nectar is one that is used for a diluted juice to denote a beverage that contains fruit juice and water, and which may contain sweeteners. Smoothies Fruit smoothies are typically combinations of homogenized/crushed fruit and juice (Landon, 2007). Most single servings of commercially available fruit smoothies (typically 250 ml) contain at least one 80 g portion of whole fruit, as well as one portion of fruit juice (150 ml). ÔIntrinsicÕ and ÔAddedÕ Sugars Naturally occurring (intrinsic) sugars refers to sugars that are an integral part of whole fruit, vegetable, and milk products (Johnson et al., 2009) while added sugars are defined as sugars (mainly monosaccharides and disaccharides) and syrups added to foods and beverages by manufacturer, cook or consumer during processing or preparation, including sugars and syrups added at the table. They are also referred to as free sugars (Johnson et al., 2009). Total Soluble Solids (TSS) They are defined as the sum of the solids which are dissolved within a substance and it is usually expressed in degree Brix (Maireva et al., 2013). Degree brix is the mass of soluble solids (mainly sugars) contained in 100 g of solution. Sugar and fruit acids are the main contributors to the total soluble solid contents of fruit juices; however, pectins, glycosidic materials and the salts of metals when present also register a small but insignificant influence on the TSS content. 17 18 1.2 Fruit Juice Fruit juice is an unfermented but fermentable liquid or juice intended for direct consumption, obtained from the edible portion of sound, appropriately mature and fresh fruit by mechanical extraction process and preserved exclusively by chemical and physical means (Oranusi et al., 2012). Fruit juice is a fruit product, which could be easily consumed by infants, children and adults to meet their nutrient needs, particularly that of micronutrients (Nnam and Njoku, 2005; Nzeagwu and Onimawo, 2010). It can be freshly squeezed or made from concentrate. 1.2.1 Fresh Juice Freshly squeezed juices are produced by ÔsqueezingÕ the juice from the fruit of choice, which is then packaged and transported to the retailer usually within 24 hrs. These juices often do not undergo any form of pasteurization and therefore typically have a very short shelf life usually 2-3 days. However, they may undergo high-pressure treatment and/or modified-atmosphere packaging to increase their shelf life. The term ÒF resh JuiceÓ in most cases applies to those juices prepared in front of the consumer. If the juice is pasteurized, or contains juice concentrates or ÒstoredÓ juices, then it is not fresh juice (Cashwe ll, 2009). 1.2.2 Reconstituted Juices A reconstituted fruit juice is the product obtained by replacing the water extracted from the juice during concentration, and by restoring the flavours. They are commonly referred to as juice Ôfrom concentrateÕ. They are common to commercial j uices where there is need to increase shelf life as well as the ease of transportaion. The juice is extracted from the fruit the same way as done for fresh juices after which the extracted fruit juice is concentrated by evaporating the water naturally present in it. This concentrate is properly preserved often by freezing before being transported to its destination, where water is added back to reconstitute the juice to 100% fruit juice or alternatively, the concentrate can be used as an ingredient in a cordial drink. After reconstitution, fruit juices from concentrate are typically pasteurized, to ensure that any unwanted spoilage pathogens, including bacteria or moulds, are destroyed. The shelf life of the product is determined by the temperature of pasteurization. Long-life products are those products pasteurized at a temperature of approximately 90¡C for a short time usually10-20 seconds. They have a shelf life of approximately 6-9 months. Short-life products are pasteurized at a lower temperature (70-75¡C) for 10-20 seconds and product s typically have a shelf life of 2-6 weeks (Cashwell, 2009). 18 19 1.2.3 Common Fruits and Fruit Juices Fruits have been a part of human diet over the years. They are also considered as food supplements and are recommended internationally as essential to healthy nutrition, because they contain high quantity and quality of water, sugars, vitamins and minerals (Ndife et al., 2013). Fruit consumption has been reported to contribute to the prevention of degenerative processes, particularly lowering the incidence and mortality rate of cancer and cardio-cerebrovascular diseases (Krejpcio et al., 2005). They contain phytochemicals which act against oxidative reactions in the human body (Vanamala et al., 2006; Okwu and Emenike, 2006). Fruits and vegetables are very perishable in nature; therefore high post harvest losses resulting from lack of cold storage facilities on the farms, improper handling and inadequate processing facilities occur immediately after harvest, during distribution and marketing (Alaka et al., 2003; Landon, 2007; Adubofuor et al., 2010; Ndife et al., 2013), hence the need to process them into fruit juices. 1.2.3.1 Apple Juice Apple (Malus domestica) features oval or pear shaped (Figure 1). Its outer peel comes in different hues and colours depending upon the cultivar type. Internally, its crispy, juicy pulp is off-white to cream in colour, and has a mix of mild sweet and tart flavour. Figure 1: Fresh apple (Malus domestica) Apples (Malus domestica) are one of the healthiest foods a person can eat. Studies suggest that its components are essential for optimal growth, development, and overall wellness. They are 19 20 high in fiber, low in calories, have only a trace of sodium, and no fat or cholesterol. Apples have been shown to have potent antioxidant activity that can greatly inhibit the growth of liver cancer and colon cancer cells (Eberhardt et al., 2000). They are high in polyphenols and notable for their impressive list of phytonutrients and antioxidants including flavonoids. Some of the important flavonoids in apples are quercetin, epicatechin, and procyanidin B2 which help protect the body from deleterious effects of free radicals (Boyer and Liu, 2004). Apple contains good quantities of vitamin C which is a powerful natural antioxidant. Consumption of foods rich in vitamin C helps the body develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals from the body. Apple is a good source of B-complex vitamins such as riboflavin, thiamin, and pyridoxine (vitamin B6). Together, these vitamins help as co-factors for enzymes in metabolism as well as in various synthetic functions inside the human body (Eberhardt et al., 2000). Apples also contain small amount of minerals like potassium, phosphorus, and calcium. Potassium is an important component of cell and body fluids that helps control heart rate and blood pressure through countering sodium actions (Soetan et al., 2010). 1.2.3.2 Orange Juice Orange (specifically, the sweet orange) is the fruit of the citrus species, Citrus sinensis in the family Rutaceae (Figure 2). Oranges, whose flavor may vary from sweet to sour, are commonly peeled and eaten fresh or squeezed for juice. Figure 2: Sweet orange (Citrus sinensis) Delicious and juicy orange contains an impressive list of essential nutrients, vitamins, minerals for normal growth and development and overall well-being. Nutrients in oranges are plenty and 20 21 diverse (Franke et al., 2005). The fruit is low in calories, contains no saturated fats or cholesterol, but is rich in dietary fiber, pectin. They are an excellent source of vitamin C, which is a powerful natural antioxidant. Oranges contain a variety of phytochemicals. They contain very good levels of vitamin A, and other flavonoid antioxidants such as alpha and beta-carotenes, beta-cryptoxanthin, zea-xanthin and lutein which are known to have antioxidant properties. Vitamin A is required for maintaining healthy mucus membranes and skin and is essential for vision. Consumption of natural fruits rich in flavonoids protects the body from lung and oral cavity cancers (Ndife and Abbo, 2009). Flavonoids especially flavonones in oranges have been shown to possess several physiological properties which can help inhibit cell proliferation and promote cell differentiation (Vanamala et al., 2006). Orange is a very good source of B-complex vitamins such as thiamin, pyridoxine, and folates. These vitamins are essential in the sense that the body requires them from external sources to replenish. Orange also contains a very good amount of minerals like potassium and calcium.

 

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