Appearance, flavor, texture and nutritional value are the major attributes that are considered by consumers when making food choices. Appearance which is significantly impacted by color is one of the first attributes used when evaluating food quality (D. M. Barrett, 2010). Color may be influenced by naturally-occurring pigments in food or by pigments resulting from both enzymatic and non-enzymatic reactions (Sporns, 2005). Enzymatic browning is one of the most important color reactions that affect the fruit industry.
Enzymatic browning usually impairs the sensory properties of products due to associated changes in color, flavor and softening; which takes place during processing and storage as well as when fresh fruits are subjected to mechanical injury. This discoloration presents a serious problem in the food industry. Control of enzymatic browning in minimally processed fruits has received attention by researchers because of its importance to the food processing industry. Historically, enzymatic browning has been controlled by the application of sulfites. Sulfites are multifunctional agents; they prevent enzymatic and non-enzymatic browning, control growth of microorganisms, act as bleaching agents and antioxidants or reducing agents, and carry out various other technical functions. However, the use of sulfite has some disadvantages. In the US, sulfites compounds are generally recognized as safe when used in accordance with good manufacturing practices, except that they are not allowed to be used on fruits and vegetables intended to be served raw to consumers or sold raw to consumers (FDA,1996). Sulfites have been used to prevent browning; however, there is a need to substitute sulfites with other methods of preservation. In theory, polyphenoloxidase catalyzed browning of fruits and vegetables can be prevented by heat inactivation of the enzyme, exclusion or removal of the substrates, lowering the pH to 2 or more units below the optimum, or adding compounds that inhibit polyphenoloxidase or prevent melanin formation such as ascorbic acid, citric acid, benzoic acid (Whitaker & Lee, 1995). Since Kamias (Averrhoa bilimbi) mainly contains a high percentage of oxalic acid which is a type of citric acid, the researcher decided to utilize its high acidity as an effective inhibitor.
Various physical and chemical methods have been used to control browning and/or inactivate its activity. These methods would mostly influence the browning through the nature of the reactant, temperature and pH level. Color deterioration can therefore be inhibited by controlling these factors. Although storage at low temperature is an efficient way, the activity cannot be completely inhibited and the expense associated with keeping foods cold is a considerable problem. Any effective anti-browning agent that can preserve it at room temperature for a long time is the potential solution to this problem. Statements of the Problem
The main problem of this proposed study will be to determine if Kamias (Averrhoa bilimbi) fruit extract would be more effective when used as an enzymatic browning inhibitor compared to other known inhibitors. Specifically, it will seek to answer the following questions: 1. How would Kamias (Averrhoa bilimbi) fruit extract be effective as an enzymatic browning inhibitor? 2. Is there a possibility to produce an enzymatic browning inhibitor from Kamias (Averrhoa bilimbi) fruit extract to be applied on apples? 3. How effective is the Kamias (Averrhoa bilimbi) fruit extract in inhibiting enzymatic browning activity if various concentration of the mixture would be applied directly to the apples for three days? Significance of the Study
This study is about producing an enzymatic browning inhibitor from the fruit extract of Kamias (Averrhoa bilimbi) that would be...