Madras Agric. J. 92 (10-12) : 667 - 669 October-December - 2005

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TESTING OF A BLACK PEPPER DECORTICATOR A. KARTHIAYANI, AEC & RI, TNAU, COIMBATORE Abstract : The performance of a power operated black pepper decorticator was evaluated. The major parts were a cylinder with a rough inside surface, rotating shaft with vane arrangement, feed hopper, collecting tray and an electric motor with a speed reduction unit. Experiments were conducted at different soaking periods, operation time and feed rate. The study showed that the parameters of soaking period, operation time and quantity of feed have significant influence on overall decorticating efficiency. A soaking period of 5 days, time of operation of 1.5 minutes and feed rate of 5-g/ batch was found to provide an overall decortating efficiency of 86 per. Key words : black pepper, white pepper, decorticator, oleoresin, volatile oil

INTRODUCTION Spices play an important role in the day today diet of the people. It is considered particularly indispensable in the culinary arts, adding savour to the insipid dishes, tang to beverages and zest to the appetizers. India is considered as the home of spices having favorable climatic and soil conditions. Though India is the largest producer of spices accounting for 61 per cent of world production and 39 percent of total export, it secures only 9 per cent in terms of value. The reason being the country does not produce high quality spices that fetch good price and spices are exported raw without any value addition. So the country is bound to concentrate on the quality addition to spices and value added products. Black pepper (piper nigrum), the King of spices is cultivated in an area of 21 lakh hectares in India. The annual production of the crop is 0.6 lakh tons and productivity works out to be 285 kg / ha (Rajagobalan, 1996). The important value added products of pepper include white pepper, dehydrated green pepper, pepper powder, pepper oil and oleoresin. The world demand for white pepper is estimated to be about 30, 000 to 40, 000 tonnes per annum. The major part of the white pepper export in the market is shared by Indonesia, Malaysia and Brazil. India’s contribution is very insignificant. India is lagging far behind the other pepper producing countries in white pepper output, not withstanding the fact that India accounts for more than half of the world area cultivating pepper and

production of about 1/3 of the total world production of pepper. Though white pepper is superior to black pepper, Indian farmers are reluctant to resort to white pepper production. The main reason being the absence of convenient and easy method for the production of white pepper. Microbial fermentation is widely used method, but it is time consuming and it deteriorates the quality. Steaming is also employed for white pepper production, but it involves high cost and quality loss due to cooking. A better solution is mechanical decortication, which does not require additional facilities like running water, water tank etc. and large volumes of materials can be processed in a shorter period of time. Hence a study was proposed for development and testing of black pepper decorticator. MATERIALS AND METHODS: Pepper (Piper nigrum), Panniur I variety was used for the study. The berries were cleaned for impurities, brokens and foreign materials. The moisture content was determined by toluene distillation method using Dean stark apparatus a per AOAC (1975) method. The shape was found by using traveling microscope and the sphericity was found by using standard formula. The bulk density and true density were determined by using standard methods. The pepper berries were soaked in water for 1,2,3,4 and 5 days to soften the outer skin. A measured quantity of soaked pepper berries was fed through the feeding hopper. When the machine

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was started, the berries were subjected to centrifugal force due to which, they move to the periphery of the cylinder. The rubber flaps carry the berries and rub them against the rough inside surface of the cylinder. This causes the mesocarp to rub off from the core and thus the decortication takes place. The decorticated berries were collected from the outlet arrangement.

Fig (1) reveal that there is a gradual increase in overall efficiency up to the fourth day. The increase in decorticating efficiency with soaking is attributed to the softening of skin. From fifth day onwards the decorticating efficiency starts decreasing due to increase in amount of broken. It is found that the optimum soaking period was about 5 days for maximum decortication with minimum losses.

Decorticating efficiency:

Effect of time of operation on overall decorticating efficiency: For constant feed rate of 2.5g/batch and soaking period of 5 days, the experiment was conducted for different times of operation (Fig 2). 1.5 min of operation gave the maximum efficiency of 86.5 per cent.

Decorticating efficiency is defined as the ratio of the weight of decorticated berries to that of total whole berries fed to the system. Effectiveness of wholeness of kernels: Effectiveness of wholeness of kernels is defined as the proportion of whole kernels to the total quantity of kernels (whole + crushed). Overall decorticating efficiency: Overall decorticating efficiency is defined as the product of decorticating efficiency and effectiveness of wholeness of kernels. The overall performance of the machine is expressed by this term as it takes into account both qualitative and quantitative aspects of operation. RESULTS AND DISCUSSION Effect of soaking period on overall decorticating efficiency: The machine was operated at constant feed rate of 2.5g/batch and time of operation of 2 min.

Effect of quantity of feed on overall decorticating efficiency: For 5 days soaked samples and 1.5 minutes of operation, the machine was operated for different feed rates. 5g/batch of feed gave the optimum decorticating efficiency (Fig 3). Efficiency of the machine: The overall decorticating efficiency of the machine under the optimum condition of operation was found to be 86 per cent, the effectiveness of wholeness of kernels being 1. Analysis of white pepper: The volatile oil was found to be 2.1 per cent. The data on gas chromatographic analysis of white pepper is shown in Table 1.

Table 1 : Gas chromatographic analysis of white pepper Constituent

Black pepper (%)

White pepper (%)

Pinene

7.852

6.586

Myrcene

10.650

10.533

Limonene

18.811

14.635

β - Caryophyllene

30.369

30.089

A slight decrease in the low boiling constituents like pinene, myrcene and limonene was noted. This may be due to heat generated during the operation. The change in the high boiling constituents like β-caryophyllene was found to be negligible.

The study showed that the parameters of soaking period, operation time and quantity of feed have significant influence on overall decorticating efficiency. A soaking period of 5 days, time of operation of 1.5 minutes and feed rate of 5-g/ batch was found to be the optimum values. An overall decorticating efficiency of 86 per cent was obtained.

AOAC (1975). Official methods of analysis. Association of official Analytical Chemisists. Benchanmin, Frankelin station, Washington. PP: 563.

Rajagopalan (1996). Variability in black pepper cultivars. Journal of Spice crop 12(2): 154158.

Fig 1 : Effect of soaking period on overall decorticating efficiency

Fig 2 : Effect of time of operation on overall decorticating efficiency

Fig 3 : Effect of feed rate on overall decorticating efficiency

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