Super Critical Fluid Extraction of Natural Antioxidants for Food Preservation from Spices and Non Conventional Fruits Endemic in North Eastern Region:
Phytochemicals in the strictest sense are chemicals produced by plants having different biological activities, but are not essential nutrients means these are not essentially require for the basic process of growth and development. Plants produce these chemicals to protect themselves from biotic (insects, pests, pathogens, predators etc.) and abiotic stress (drought, heat, cold, submergence etc.) and phytochemicals can also improve humans health and protect against diseases. Phytochemicals are extensively used in food, pharmaceuticals, and cosmetic industries as antioxidants, food additives, flavoring agents, sweeteners, sugar substitutes, coloring substances, drugs and antimicrobial agents etc.
Antioxidants play a major role in preventing or delaying autoxidation and have attracted much attention as food stabilizers, dietary supplements and natural health products. The oxidative deterioration of fats and oils in food is responsible for rancid odors and flavors, with a consequent decrease in nutritional quality and safety caused by the formation of secondary, potentially toxic compounds. The addition of antioxidant is required to preserve flavor, color and to avoid nutrients degradation. Currently, the food process industries are using synthetic antioxidants like butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT) propyl gallate (PG) and tertiary-butyl hydroquinone (TBHQ) to prolong the storage stability of food product. Some reports have indicated that certain synthetic antioxidants such as BHA and BHT may possess carcinogenic effect and have other health hazards in animals. In addition, use of synthetic antioxidants like TBHQ is restricted in many countries. Therefore, it is proposed to develop process to isolate natural antioxidants like ascorbic acid, tocopherols, catechin, lecithin, quercetin, ?-oryzanol, sesamol, etc. from whole spices, herbs, vegetables, or leaves, stems, roots, fruits, seeds, grains and other parts of different plants which are abundant in NE India Region (3 PhD students are working in this area). Super critical fluid extraction process delivers a superior extract which has incredible purity and is highly concentrated. This extraction leaves no harmful residues and the process use natural carbon dioxide unlike solvent extraction with industrial solvents like hexane and acetone where harmful residues of such chemicals may remain in the extract. The microencapsulated Supercritical Fluid Extracted product will be used as a replacement to synthetic antioxidants for food preservation. The natural antioxidants have anti-ageing, anti-carcinogenic, anti-mutagenic, immune protective and many other beneficial effects and therefore can also be used in preventive and therapeutic medicine as well as neutraceuticals in India and abroad. Other products of the process, beside antioxidants, can be used for various purposes. e.g. Essential oil and fixed oils have a wide range of applications in many industries like food processing, pharmaceuticals, soft drink, confectionary and cosmetic industries. Moreover this will fulfill the consumer's demand of safer and natural products. Consequently, the market will increase for such naturally preserved food products which will earn remunerative prices in domestic and export market. This work is carried out in collaboration with Prof. L Sahoo (Dept. of Biotechnology, IIT Guwahati).