Antioxidant Activity of Banana Peel

According to several authors, banana peel recorded stronger antioxidant activity, pooled more quantity of phenolic compounds (Someya et al., 2002), greater range of phenolics composition and higher in minerals content than banana pulp. Banana pulp had been reported as having various antioxidants such as vitamins (A, B and E), β – carotene (Kanazawa & Sakakibara, 2000) and phenolic compounds like catechin, epicatechin, lignin, tannin (Someya et al., 2002), gallocatechin and anthocyanins like peonidin and malvidine.

There several type of antioxidant such as vitamin C, E, A, beta-carotene, lycopene and also other substances. Antioxidants are abundant in fruits and vegetables, as well as in nuts, grains, and some meats, and fish. Combination of vitamin C with other antioxidants, including vitamin E, b-carotene, and selenium, provides a synergistic antihypertensive effect. Experimental evidences prove that antioxidants can protect human body from free radicals and reactive oxygen species (ROS) effects. Antioxidants are substances that can prevent or slow the oxidative damage to our body and also may protect cells from the damage caused by free radicals. Free radicals are unstable molecules or highly reactive chemical that often contains oxygen and is produced during oxidation. Exposure to various environmental factors will lead to free radical formation such as tobacco smoke and radiation. Free radicals can damage important cellular molecules such as DNA or lipids or other parts of the cell and also may lead to cancer.

Banana peel also demonstrated the presence of various phenolic compounds such as gallocatechin and anthocyanins like peonidin and malvidin. Phenolic compounds are secondary metabolites, which have been associated with flavour and colour characteristics of fruits and vegetables and are gaining considerable attention because of their potent antioxidant and health promoting properties (Kaur & Kapoor, 2001). Extraction of phenolic compounds in plant materials is influenced by many factors including the extraction method employed, types of solvent polarity used, storage time, presence of interfering substances, sample particle size and conditions as well as their chemical nature.

Bananas were enriched with minerals like potassium, phosphorus, magnesium and calcium. Banana peel could be a good source of carbohydrates and fiber. The high fiber content also indicates that the peels could help treat constipation and improve general health and well being (Anhwange, B. A. et al., 2009).

Natural antioxidant are compound from plant or animals sources that retard oxidative rancidity of oil, fats and fat soluble components, thus protecting them while delaying the development of unpleasant flavors and odors resulting from oxidation process. Antioxidant are present naturally in most raw food sources. Processing of the fruit can remove or trigger the degradation of these antioxidant. Nowadays, the most widely used antioxidant were synthetic antioxidant such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroxyanisole (TBHQ), and propyl gallate (PG). Figure 1.1 show the molecular structure of the available synthetic antioxidant.

Problem Statement

Doubt on the safety of the synthetic arose first in the 1960s and led to an increased interest and broad research on natural antioxidant (). Natural antioxidant particularly found in fruit and vegetables have gain interest among consumer and the scientific community because epidemiological studies have indicate that frequent consumption of natural antioxidant is associate with the lower risk of cardiovascular and cancer (Renoud et al.1998). Natural antioxidants are perceived safe, less toxic and beneficial for human health. However, natural antioxidants is very expensive and have been not widely commercialized.

In the recent years, there had been an explosive interest in studying antioxidants of some fruits due to their health promoting properties. A large number of studies have been demonstrated either on the effect of extraction time and extraction temperature or drying temperature toward antioxidant activity, phenolic content and minerals in banana peel. Antioxidant activity could influence by geographical origin, cultivar and harvest storage time. (C. Guo et al., 2003). These statements show that different origin of banana peel will have different value of antioxidant. This present studies are focusing on the banana peel that originally harvest in Malaysia because banana peel from Malaysia origin is rarely being studied before.

Objective

The objective of this research project is to establish the optimal condition for obtaining the banana peel extract with high antioxidant activity, phenolic content and minerals by using solvent extraction.

Research Scope

Following tasks will be undertaken as a part of the proposed research:-

Different drying temperatures of 50°C, 55°C, 60°C, 65°C and 70°C used to dry the sample. 70% acetone was use as the extracting solvent. Antioxidant activity and phenolic content was analyst by using Ferric Reducing Antioxidant Power (FRAP) assay and Folin-Ciocalteu’s calorimetric (FC) respectively. The detection of the products was performed by using UV-visible Spectrophotometer.

The sample of 60°C drying temperature was extract by using different solvent (methanol, acetone and water) with different dilution ratio (90%, 70%, 50%) in the hot water extraction. The extraction was done at 50°C for 1 hour. Antioxidant activity and phenolic content were analyst by using FRAP assay and FC assay respectively. The detection of the product was performed by using UV-visible Spectrophotometer.

Time of extraction vary from 1minutes-120 minutes was used to determined the effect of extraction time on antioxidant activity and phenolic content. Banana peel drying at 60°C extracted with 70% acetone was used as the sample. Analysis were done by using FRAP and FC assay where the detection was performed by using UV-visible Spectrophotometer

Different extraction temperatures of 40°C, 50°C, 55°C and 60°C were for the hot water extraction. Banana peel drying at 60°C extracted with 70% acetone was used as the sample. Duration of the extraction process was 2 hours. Analyst for antioxidant activity and phenolic content were performed.

Verification of the Ascorbic acid existence in the banana peel extract was performed using High Performance Liquid Chromatography (HPLC) unit. Banana peel drying at 60°C extracted with 70% acetone was use as the sample. The extraction process was done at 55oC for 2 hours.

Sodium(Na), Magnesium(Mg) and Calcium(Ca) compositions in banana peel extracted with 70% acetone and undergo 2 hours extraction at 55oC were investigate by using Atomic Absorption Spectrophotometer (AAS) unit.

Rationale and Significance

Banana is one of the source of natural antioxidant. Besides, banana is easy to get because it is not a seasonal fruit and it grow well in Malaysia. Banana peels are waste from banana fruit and they contain high amount of antioxidant, phenolic content and also mineral. This peel is biodegradable and it will produce environmental problem due to it nitrogen and phosphorus quantity. Therefore extracting the banana peel will be the best solution in order to protect human being, gaining some profit and also creating waste to wealth. Banana peel also can be commercialize because it qualitative and quantitatively contain more antioxidant than it pulp. It also will have does not compete with banana pulp in producing end product especially in the food industry.