Centre for Post Harvest Technology Technologies Developed

Technologies Developed

1. Double Chamber Centrifugal De-Huller For Millets

Millets are highly nutritious with good quality protein, rich in minerals, dietary fibre, phyto-chemicals and vitamins.  People have started realizing the importance of the millet and the consumption has gone up in recent years.

De-hulling is the one of the important post-harvest operations carried out for the removal of husk from millets. At present de-hulling is carried out with the abrasive roller type machines as exclusive de-huller for the millets are not available.  In this process, along with the husk, bran and small portion of endosperm is also removed which leads to the depletion of nutrients. Moreover the de-hulled grains contain about 20% of brokens. To overcome these problems, a double chamber centrifugal de-huller has been developed at Post Harvest technology Centre, Agricultural Engineering College and Research Institute, Coimbatore.

The developed de-huller essentially consist of feed hopper, two centrifugal chambers made of cast iron, impellers with curved vanes, blower and separate outlets for collecting kernel and husk. The unit is powered by 5 h.p. motor with suitable power transmission system. An elevator is also provided for easy feeding of the grains in to the unit. In operation the grains from the hopper enter the impeller through feed housing where it gains momentum and thrown against the cast iron chamber at very high velocity. The splitting of the husk occurs due to impact and the kernel comes out of the husk. The husk and kernel mixture passes through a chamber where they are get separated by means of a blower provided at the bottom of the unit.

 Special features

  • 10 % more recovery (since the bran is retained   in the kernel )
  • Suitable for little millet, proso millet, foxtail millet, barnyard millet and kodo millet.
  • The capacity of the de-huller is 300 kg of per hour.
  • The efficiency of the unit is 95%
  • Breakage of 4-5%.
  • Labour required: one person
  • Cost of the unit Rs.1,20,000
  • Cost of operation Rs.5 per/kg

2. Hand Operated Aonla Seed Remover

Aonla is one of the oldest Indian fruits considered as “wonder fruit for health” because of its unique nutritional qualities and therapeutic properties. Despite the potential sourceof vitamin C traditional methods of processing provides a poor quality product with low nutrient content. Aonla fruit is perishable in nature and are available only for shorter periods. It is necessary to develop improved equipment and novel methods for new product developments for the value addition of aonla.

A hand operated equipment for the removal of seed from aonla fruit was developed at the post-harvest technology center. The equipment consists of a fruit punching rod, fruit resting seat, handle with extension and the frame to hold all the important movable parts. The parts of equipment coming in contact with fruit were made out of stainless steel (food grade) and all other parts were made of mild steel. The whole equipment was electroplated to avoid blackening of parts when it comes in contact with the fruit ascorbic acid.

Specifications of the equipment

Capacity 20 kg/hr
Efficiency of de-seeding 90 percent
Percent juice wastage 2 per cent
Cost of the equipment Rs.2000/-
Cost of operation


Hand operated aonla seed remover

3. Biocolor From Beetroot

              Biocolour from beetroot was prepared by utilizing as natural colour in processed foods by replacing the synthetic colours. The beetroot was washed in water and the outer skin and stalks were removed. The peeled beetroot was cut into small pieces and pulped by adding aqueous solution containing 3.0 per cent acetone (4 part beetroot pulp: 1 part aqueous solution). The beetroot pulp was filtered and the extracted juice TSS was adjusted to 25 ° brix by adding maltodextrin. Citric acid (0.1%), calcium sterate (0.1%) and gallnut powder (2%) was added to the juice and mixed thoroughly and filtered. The filtered juice was spray dried at a temperature of 200 °c. The stability of the biocolour from beetroot powder was studied at different levels of pH, preservative and temperature respectively. The physico-chemical characteristics of the freshly prepared biocolour from beetroot powder contained sedimentation – nil, solubility -100 per cent, acetone residues – nil, colour values 88.66, 4.57 and – 2.13   L* a* b*, moisture – 2.07 per cent, pH – 4.2, carbohydrate – 69.36 per cent, protein – 5.50 per cent, fat – 0.2 per cent, fibre – 0.28 per cent, ash – 4.8 per cent, total antioxidant – 16.36 mg /g and tannin – 2.74 per cent.. The prepared biocolour was applied in processed foods viz., beverages (milk shake), jam, jelly, candies (jujups and lollipop), sweetmeats (halwa and kesari), icings and ice-cream and the level of incorporation of biocolour was optimized. Incorporation of biocolour in processed foods was ranged from 0.2 to 0.9 per cent and the synthetic colour was between 0.01 and 0.03 per cent. Organoleptic evaluation studies showed that the overall acceptability the processed products ranged from 8.0 to 8.6 initially and from 7.5 to 8.0 at the end of 180 days. For 100 kg of fresh beetroot yielded 19.0 kg of biocolour. The cost of the   biocolour from beetroot powder was Rs. 56/. per 100 gram.