The sugar and mineral levels of industrially processed fruit juices (mainly 100% and 50% fruit juices) sold to consumers in Enugu state, Nigeria were determined and compared with that of freshly prepared fruit juices. The liquid nature as well as the versatility of juice has increased the ease with which fruit juices can be altered with sugar, contaminants, water or inferior juices by unethical suppliers. This research was performed to address the potential concern that industrially processed fruit juices (especially those with ‘100% natural’ and ‘no sugar added’ label) may differ in quality with respect to sugar and mineral contents (including heavy metal contents which is deleterious to quality) from extracted juice of fresh fruit, as well as to address in part the ongoing public health concerns of excessive sugar consumption, micronutrient malnutrition and heavy metal contamination. The fruit juices tested included apple, orange, pineapple and red grape juices. All industrially processed fruit juices and fresh fruits used were purchased in Enugu state, Nigeria. The fresh fruits were juiced and all samples including industrially processed and the freshly prepared fruit juices were tested for total soluble solid (TSS) content, fructose, glucose, sucrose, Na, K, Mg, Ca, P, Fe and heavy metals contents such as Cu, Zn, As and Pb. Findings from the analysis of the TSS content of fruit juice samples demonstrated no significant (p > 0.05) difference between the industrially processed and freshly prepared fruit juices; however, difference in sugar and mineral levels between industrially processed and freshly extracted fruit juices was significant (p < 0.05). Industrially processed fruit juices contained higher glucose, sucrose, Na, Ca, P, Cu and Zn contents, and lower fructose, K and Mg contents when compared to freshly prepared fruit juices. There was no significant (p > 0.05) difference in iron (Fe) and arsenic (As) contents of industrially processed fruit juices when compared with the freshly extracted juices. Lead (Pb) was not detected in any of the samples. This study demonstrated no quality issues of concern in relation to the products because all the parameters considered in the study were within the standard acceptable range for fruit juices and nectar.



Title page





Table of contents

List of figures

List of tables

List of abbreviations



1.1       Research terminologies

1.2       Fruit juice

1.2.1    Fresh juice

1.2.2    Reconstituted Juice

1.2.3    Common fruits and fruit juices Apple juice Orange juice Pineapple Juice Red grape juice

1.3       Fruit juice processing

1.3.1    Fruit juice extraction and clarification

1.3.2    Fruit juice preservation and storage

1.3.3    Quality control

1.4       Fruit juice adulteration

1.5       Fruit juice nutrition

1.5.1    The role of fruit juice in a diet

1.5.2    Nutrients delivered by fruit juices Sugars Minerals          Sodium (Na)          Potassium (K)          Magnesium (Mg)          Calcium (Ca)          Phosphorus (P) Iron (Fe) Phytochemicals Vitamins

1.5.3    Health benefits of fruit juices Fruit juice and cardiovascular health Fruit juice, cancer and inflammation Fruit juice, brain health, cognition and ageing Fruit juice and skin health

1.6       Health concerns associated with fruit juice consumption

1.6.1    Fruit juice and obesity

1.6.2    Fruit juice and dental health

1.6.3    Heavy metals in fruit juices Zinc (Zn) Copper (Cu) Arsenic (As) Lead (Pb)

1.7       Problem statement and justification of the study

1.8       Aim of the study

1.9       Specific objectives of the research



2.1       Materials

2.1.1    Plant materials

2.1.2    Collection of samples

2.1.3    Instruments/Equipment

2.1.4    Chemicals

2.1.5    Experimental design

2.2       Methods

2.2.1    Extraction of juice from fresh fruits

2.2.2    Determination of total soluble solid (TSS) content of fruit juice samples

2.2.3    Determination of sugar contents of fruit juice samples Determination of fructose content Determination of glucose content Determination of sucrose content

2.2.4    Determination of mineral contents of fruit juice samples Wet digestion of fruit juice samples Determination of Na and K content Determination of Mg content Determination of Ca content Determination of P content Determination of Fe content

2.2.5    Determination of heavy metal content (Cu, Zn, As, Pb) of fruit juice samples

2.2.6    Statistical analysis



3.1       Total soluble solid content of fruit juice samples

3.2       Sugar contents of fruit juice samples

3.2.1    Fructose contents of fruit juice samples

3.2.2    Glucose contents of fruit juice samples

3.2.3    Sucrose contents of fruit juice samples

3.2.4    Comparison of the sugar contents of fruit juice samples

3.3       Mineral contents of fruit juice samples

3.3.1    Sodium (Na) contents of fruit juice samples

3.3.2    Potassium (K) contents of fruit juice samples

3.3.3    Magnesium (Mg) contents of fruit juice samples

3.3.4    Calcium (Ca) contents of fruit juice samples

3.3.5    Phosphorus (P) contents of fruit juice samples

3.3.6    Iron (Fe) contents of fruit juice samples

3.3.7    Comparison of the mineral contents of fruit juice samples

3.4       Heavy metal contents of fruit juice samples

3.4.1    Zinc (Zn) contents of fruit juice samples

3.4.2    Copper (Cu) contents of fruit juice samples

3.4.3    Arsenic (As) contents of fruit juice samples

3.4.4    Comparison of the heavy metal contents of fruit juice samples



4.1       Conclusion





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 (O’Neil 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.