Nanotechnology in Food Processing

Nanotechnology focuses on the characterization, fabrication and manipulation of biological and non-biological structures smaller than 100 nm. The physical, chemical and functional properties of structures at nanoscale exhibit unique and novel functional properties. Food processing in present day targets specific health and nutrition functions. Conventional food processing technologies face certain limitations and are unable to overcome the challenges. It is not possible to add water soluble vitamins fats/oils, similarly fat soluble vitamins cannot be added to juices/beverages. Nanotechnology has opened new avenues in overcoming the limitations of conventional processes, development of health / functional foods; improved nutrition, taste, color flavor and texture of food stuffs; development of nano-composites with improved barrier, mechanical or antimicrobial properties and nanosensors for traceability and monitoring the conditions of food during transport and storage. The important areas include, nano-emulsions, nano-encapsulation, nano-fibres and nano-laminates for developing functional foods; nano-membrane separation systems; nano-composites for food packaging, nano-catalysts for improving chemical/biochemical reactions, nano-sensors and nano-traces for food safety and bio security, etc. The commercialization of many nanotechnological innovations in the area of food processing has already taken place. The potential of nanotechnology in food processing is immense. 

Parameters to be measured for food testing

Physical testing – color, specific gravity, bulk density, true density, water activity, viscosity, total soluble solids, refractive index, acid value.

Chemical and Nutritional analysis

Chemical analysis – moisture, protein fat, ash, carbohydrate, reducing and non reducing sugars, starch, total calories, pH, acidity etc.

Nutritional analysis – minerals (iron, calcium, phosphorous etc), vitamins (Vit A, Vit C, Thiamine, Riboflavin, niacin folic acid etc), dietary fiber, beta carotene, lycopene, chlorophyll, anthocyanines, tannins, trypsin inhibitor, phytates etc.

Microbiological Tests - Aerobic Plate Count (APC), Yeast & Mold, Total Coliforms & E. coli, Staphylococcus aureus, Salmonella, Listeria, E. coli O157:H7, Anaerobic Plate Count, Aerobic Spore Former Count, Lactic Acid Becteria Count, Anaerobic Spore Former Count, Thermophilic Aerobic Spore Former Count, Thermophilic Anaerobic Spore Former Cont etc. 

Contaminants and Toxins – aflatoxins, mycotoxins, pesticide residues,

heavy metals, trace metals, antibiotic residues.

Water Quality – physical (clarity, color, odour and taste, turbidity), chemical (TS, bardness, alkalinity, acidity, pH, nitrates, nitrites, free ammonia, chlorides, sulphates, COD, BOD), microbiological (plate count, faecal coliforms)

Food Ingredients – food additives and preservatives (sodium chloride, sulphur dioxide, sodium benzoate, sorbic acid etc.), antioxidants (gallates, BHA etc), Synthetic colors (amaranth, erythrosine, sunset yellow, tartrazine NS, indigo carmine, brilliant black BN, annatto), artificial sweeteners (saccharin, aspartame, sucralose).   

Agro Processing Centre in ICAR Research Complex for NEH region, Barapani

Soymilk

It is creamy, milk like product rich in protein, vitamins and minerals. Soymilk is very economical, lactose free, highly digestible and nutritious. The process of preparing soymilk is very simple. It involves soaking, grinding, cooking and filtration. Soymilk can be consumed as such or after sweetening and diluting it. Soymilk can be further converted into curd or paneer. The anti nutritional factors are taken care of during processing and make the products suitable for human consumption. 

Potato based compounded animal feed pellets

Utilisation of potato processing industry waste for making feed pellet: Compounded livestock feed pellets
were prepared by incorporating potato pulp and potato chips of processing industry waste. Up to 30 % grain component was replaced by potato component. The feed samples were evaluated for their quality and trials on animal feeding were conducted. Five to seven per cent increase in milk yield of cattle was observed due to the feed.

Utilisation of unmarketable potatoes for making feed pellets: In order to utilize unmarketable potatoes
these were pulped and dewatered mechanically. It resulted in reduction in moisture content from 75 - 80 % to 40 - 45 %. The pulp obtained with reduced moisture content was directly mixed with other feed ingredients for pelletization. The feed prepared with dewatered potatoes contained 20 - 22 % of moisture. Proximate composition of feed prepared with 30 % dewatered potatoes was analysed. The feed pellets had 11.40 % moisture, 13.86 % protein, 4.96 % fat and 6 % ash. The neutral detergent fibre, acid detergent fibre, cellulose and lignin were observed to be 35, 13.4, 13 and 2.5 %. The strength of the pellets was observed to be 0.83 MPa. These samples were also subjected to animal feeding trials. Aflatoxin content of all the feed samples was analyzed using AOAC 990.33 method. The aflatoxin B1, B2, G1 and G2 were observed to be non-detected with MDL (Method Detection Limit) 30 ppb.

OHMIC HEATING SYSTEM FOR STABILIZATION OF RICE BRAN

Ohmic heating is an alternative to conventional heating. Ohmic heating has internal energy generation within its system. Major factors which influence ohmic heating include: 1) the electrical conductivity of the food substance, 2) the time that the substance is subjected to the heating, 3) the electric field strength and constancy, and 4) the temperature dependence of electrical conductivity. An ohmic heating system (Fig.1) having a capacity of 10 kg/batch was fabricated. It consists of a HDPE cylindrical container of 300 mm diameter. The bottom electrode was fixed and the upper electrode was placed on top of the material after filling the cylindrical chamber. The electrodes were made of stainless steel. A step-up isolation transformer having a rating of 10 kW and output of 450 V, 50 Hz AC was used to supply electrical power to the system. The hydrated rice bran having a moisture content of ~30 % (w.b.) was filled into the container and the upper electrode was securely placed. The electrodes were then connected to the electrical supply. The heating of rice bran started immediately and the temperature rose to around 100 ^oC in ten minutes. The heated rice bran was taken out from the system and dried. The FFA of treated and raw rice bran was measured at regular intervals. The % FFA in treated (ohmically heated) bran was observed to be 4.77 % after 75 days of storage whereas it was 41.84 % in case of raw bran. Ohmic heating effectively checked the development of FFA in rice bran. The peroxide value and acid value of ohmically heated samples after 75 days of storage were 4.7 meq/kg and 9.34 % respectively.