Thesis Abstract

Abstract
Biscuits are popular snacks consumed worldwide, and there is a growing interest in enhancing their nutritional quality by incorporating functional ingredients. This study aimed to investigate the chemical composition, health-promoting potentials, and storage properties of biscuits supplemented with orange peel and pulp flours. Orange peel and pulp flours were incorporated into the biscuit formulations at different levels (0%, 5%, 10%, and 15%). The proximate analysis showed that the addition of orange peel and pulp flours increased the dietary fiber content, while the fat content decreased in the biscuits. The biscuits fortified with orange peel and pulp flours also exhibited higher levels of bioactive compounds such as phenolics, flavonoids, and vitamin C compared to the control biscuits. Furthermore, the antioxidant activity of the fortified biscuits was significantly higher than that of the control biscuits, indicating the potential health-promoting benefits of the orange peel and pulp flours. Sensory evaluation results revealed that the overall acceptability of the biscuits decreased with increasing levels of orange peel and pulp flours; however, they were still well-liked by the panelists. In terms of storage properties, the fortified biscuits showed good shelf stability in terms of moisture content, water activity, and peroxide value during the six-week storage period. Overall, the results of this study suggest that the supplementation of biscuits with orange peel and pulp flours can improve their nutritional profile by increasing dietary fiber content and enhancing the levels of bioactive compounds and antioxidant activity. These fortified biscuits also demonstrated good storage stability, making them a promising functional food product with potential health benefits. Further research could focus on optimizing the formulation to improve sensory acceptability without compromising the health-promoting properties of the biscuits. The development of such functional biscuits could offer consumers a convenient way to incorporate bioactive compounds from orange peel and pulp into their diets, contributing to overall health and well-being.

Thesis Overview

INTRODUCTION

            Sweet orange is one of the most important fruits in the tropical and sub-tropical regions of the world. The fruits are usually eaten fresh but are also used for making canned orange juice, frozen juice concentrate, jams, jellies among others. Orange processing industries generate huge amounts of orange peel and pulp as by products from the industrial extraction of orange juices. These peel and pulp contain among other things high levels of vitamin C, dietary fibre and flavonoids. Dietary fibre has been used for the treatment of various gastrointestinal disorders and for such possible health benefits as lowering cholesterol levels, reducing risk of colon cancer and losing weight (Friedman, 1989). Dietary fibre has also been reported to have some nutraceutical potentials (Weingartner et al., 2008). Orange peel and pulp also contain other phytochemicals such as polymethoxylated flavones (PMF) and hesperidin which have hormonal and antioxidant actions and are also involved in enzyme stimulation (Gardon, 1990).

Until just recently, analysis of food was limited to sensory and its nutritional value. However, there is growing evidence that other components of food may play an integral role in the link between food and health (Kaira, 2003). Consumers are increasingly interested in the health benefits of food and have begun to look beyond the basic nutritional benefits to the potential disease prevention and health enhancing compounds contained in many foods (Hasler, 2003).

Nutraceutical, a term combining the words “nutrition and pharmaceutical,” is a food with a medical health benefit, including prevention and treatment of disease. This definition includes any substance that may be considered a food or part of a food and provides medical or health benefits, including the prevention and treatment of disease. Such products may range from isolated nutrients, dietary supplements and diets to genetically engineered foods, herbal products and processed foods such as cereals, soups, beverages among others. (Defelice, 1994). Examples of foods with nutraceutical values are broccoli (Sulforphane), which may help in the prevention of cancer, resveratrol from red grape products as an antioxidant, flavonoids in citrus, tea, wine and dark chocolate (Weingartner et al., 2008). Many botanical and herbal extracts such as ginseng, garlic oil etc have been developed as nutraceuticals. The use of nutraceuticals to accomplish desirable therapeutic outcomes with reduced side effects as compared with other therapeutic agents has met with great success (Whitman, 2001; Nelson, 1999). The peel and pulp of orange fruits have been noted to contain some bioactive substances believed to possess nutraceutical potentials (Kootstra, 1994). Thus, the incorporation of orange peel and pulp into wheat flour for the production of biscuit would enhance greater utilization of phytochemicals in Nigerian diets.

Biscuit is a confectionary, dried to very low moisture content (Okaka, 1997). Biscuit is a snack food which can be eaten in-between meals or at any time of the day and by any age bracket. An increasing proportion of the household food budget in Nigeria is spent on snacks in which convenience and quality are perceived as most important (Lasekan and Akintola, 2002). Biscuits contain fat (18.5 %), carbohydrate (78.23%), ash (1.0 %) and salt (0.85 %) (Okeagu, 2001). They are generally characterized by a low moisture content (Okaka, 1997), The shelf life is several months under correct storage conditions (Ihekoronye, 1999). However, biscuits must be packaged in containers which prevent moisture uptake (Okaka, 1997).

 

1.1 STATEMENT OF PROBLEM

The juice obtained from orange fruits is widely consumed while the pulp and peel are discarded. The amount of peel and pulp obtained from citrus fruit processing accounts for 50% of the original amount of the whole fruit (Chon and Chon, 1997). These Peel and Pulp contain some bioactive substances believed to have nutraceutical potentials.

Biscuit consumption among children and adult is high in Nigeria. Orange peel and pulp could be incorporated into wheat for biscuit production because of their phytochemical content. However, the storage properties and nutraceutical potential of biscuit containing orange peel and pulp need to be assessed.

 

1.2 BROAD OBJECTIVE OF THE STUDY  

The broad objective of the study was to determine the chemical composition, health promoting potentials and storage stability of biscuits supplemented with orange peel and pulp flours.

 

1.3 SPECIFIC OBJECTIVES

1) To produce biscuits from blends of wheat and orange peel and pulp flours.

2) To determine the chemical composition of the biscuits.

3) To evaluate the health promoting potentials of the biscuits using bio-assay study.

4) To determine the storage stability of the biscuits.