All stages of producing peanuts to trade this product 8
Salted groundnuts are very popular in Western India and prepared by soaking the groundnut kernels (HPS) in water with 4 percent common salt (NaCl) solution for 12 hours (please see Figure 26). Soaked kernels are dried and roasted with sand. If the skin is pealed off and the roasted kernels are packed in attractive packs it may add to their value. Kernels like these are sometimes served on Indian AirLines flights.
Figure 26: Salted groundnuts, very popular in West India, are being processed.
Frozen unshelled groundnut product
Quick-freezing and low temperature storage technique is widely used for food processing keep freshness and quality of the product. This technique was applied to fresh, unshelled groundnut to develop a new type of product, which could maintain fresh taste and nutritive values even after several months of storage. Immature pods were harvested around 10 to 20 days before full maturity, washed and steamed at 105°C for 5 minutes to stop enzyme activity. After vacuum packing (at -760 mm Hg for 10 min) in 0.08 mm polyvinyaldichloride film, the pods were immediately frozen groundnut investigated after 2 months of storage and compared to those of conventionally dried groundnuts. When thawed after 2 months storage, the kernels were very palatable with softness and fresh taste. This study suggested that frozen groundnut can be consumed after the steaming and freezing technique described above. However, such groundnut will require transportation under cold storage to deliver this product safely to consumers.
Groundnut milk can be prepared by soaking kernels in 1 percent sodium bicarbonate (NaHCO3) solution for 16 to 18 hour, drain off the water and grind the kernels in aqueous medium. Steep the wet mass for 4 to 5 hour and filtre through cheesecloth to remove the product. In India groundnut milk called Miltone® is a commercial reality. Miltone® consists of groundnut milk extended with buffalo milk. Groundnut milk can be used in the preparation of yoghurt-like products, ice cream and other products. Following steps may be followed to prepare groundnut milk.
- Shelled groundnuts
- Add groundnuts to boiling water, remove from heat and let soak for 7 minutes
- Drain, remove skins, soak the cotyledons in 2% NaHCO3 overnight
- Rinse cotyledons with tap water, blend in warming blender with water (1:5 w/v) for 4 to 5 minutes
- Filtre the homogenate through 4 layers of cheese cloth
- Add whey powder to the filtre at 4% level (w/v), mix thoroughly for 1 hour and boil for 10 minutes
- Groundnut milk
Source: Singh, B. 1992, ICRISAT
Preparation of mishi
Mishi is concentrated, spiced yoghurt prepared from whole milk in Sudan and usually consumed along with bread. Mishi can also be prepared from peanut milk by following the steps:-
- Groundnut Milk
- Boil for 3 minutes, cool to 45°C and inoculate with yoghurt culture (1:1 mixture of Lactobacillus bulgaricus and Streptococcus thermophilus grown in whole milk for 6 hours) at 5% level
- Incubate at 45°C for 16 hours
- Add spices (garlic 1.7%, whole cayenne pepper-0.8%, whole black pepper-0.15%, ajwan – 0.15%)
- Refrigerate the mix for 24 hours
- Drain whey through 4 layers of cheese cloth
- Add salt at 1% level
Source: Singh, B. 1992, ICRISAT
Groundnut yoghurt may be prepared by the pasteurization of groundnut milk containing 5 percent lactose. After cooling inoculate with yoghurt culture and incubate at 37°C for 4h. Final product before consumption may be refrigerated.
The formulation contains 72 percent finely ground groundnuts, 12 percent maltose syrup, 9.5 percent finely ground sugar, 3 percent roasted desiccated coconut, 2 percent finely ground rice, 1 percent roasted sesame (Sesamum indicum) seed and 0.5 percent salt. Mix all the ingredients at 60°C and pass through a peanut-butter mill. Press the mixture into a rectangular-shaped mould.
The technology now exists for the production of groundnut proteins in the form of concentrates and isolates, which are acceptable for human consumption. Groundnut protein isolates are akin to soy protein isolates (please see Figure 29). Defatted materials obtained from oil extraction processes may be soluble in neutral to base reaction washes to extract much of the protein which subsequently separated from the whey formed by reducing the pH to isoelectrical levels. Isolates once separated are neutralized with alkali and may be spray dried.
Groundnut cake or meal can be used for human consumption after partial hydrolysis of the component protein by fermentation using certain moulds. Such products are racially digestible and nutritious. Spray-dried groundnut protein isolate can be used to replace non-fat milk solids in the ice cream. Chocolate-flavoured groundnut beverage containing 3.5 percent groundnut protein, 3.5 percent fat, 8 percent sugar, 0.7 percent cocoa powder, 0.1 percent stabilizer and water can be produced. Groundnut seed protein isolates may be prepared by following the steps given in Figure 29. Coprecipitated isolates containing 95 percent protein can be prepared from various combinations of groundnut seed, cottonseed and soybean flours by following the procedure mentioned in Cereal Chemistry. 56:95 (1979), American Association of Cereal Chemistry and also given in the book by Patee and Young, 1982. Fortified milk systems were prepared by blending pasteurized standardized whole milk with dried skim milk, groundnut flour or groundnut protein isolate, to increase the TS to 15, 18, 20 or 23 percent. This was followed by processing at 60 or 80°C for 30 min and storage at 4°C for 24 hours. Curds were prepared by lactic culturing of the processed milk systems. The theological properties showed that all the systems exhibited pseudoplastic flow. The flow became less Newtonian with increasing TS, heat treatment and storage time. Curd obtained from fortified milk processed at 80°C showed increased yield stress along with curd strength with enlarged concentration of added protein. Degree of heat treatment, TS and storage had a pronounced effect on the apparent viscosity, consistency index and yield stress of the fortified milk systems (Ramana and Ramanathan, 1992).
- Blanched groundnut seed
- Grind, hexane de-fat
- Flour extraction (dilute alkali pH 9.0)
- Protein liquor
- Precipitate (Iso-electric pH 4.5)
- Wash and concentrate
- Protein curd
- Dry 9. Neutralize and dry
- Protein isolate (Isoelectric form) 10. Protein isolate (salt form)
Source: Patee and Young, 1982.
Commercial manufacture and consumption of groundnut butter is largely an American art. About half of the edible groundnuts are used for groundnut butter. Groundnut butter is mainly used as a spread for bread or biscuits, in cookies, in sandwiches, in candies and frostings or icings. It is fair sources of calcium, iron, thiamine, riboflavin and excellent source of niacin. Manufacture of groundnut butter involves roasting for controlled browning at 160°C for 40 to 60 minutes; cooling to stop the cooking process of roasting; a dry blanching operation to remove the skins (testa); and a grading or sorting operation to remove light, scorched or discoloured kernels. Several varieties of groundnuts may be optionally combined and ground to a paste or butter according to the form of product desired. Additions of salt, stabilizers and other optional ingredients including sweeteners are metered and blended with the butter prior to cooling and packaging. Other additives include hydrogenated vegetable oil, antioxidants, honey, lecithin, whey etc. The butter is used as spread on bread and in the manufacture of candy, cookies, sandwiches, wafers, patties and bars, etc.
Groundnut cheese is a novelty item that may compete in price and quality with animal cheese. Cheese like products have been made from groundnut like protein isolate just as cheese is made from cow’s milk. It has good quality protein, is easily prepared and low in cost. It is being used for “Mixed” feeding of undernourished groups in the developing countries. A processed cheese spread has been prepared from groundnut protein based tone milk in India. It has a smooth consistency and milky flavour. The flavour and other organoleptic qualities are comparable with the standard cheese.
Groundnut cake or meal can be used for human consumption after partial hydrolysis of the component protein by fermentation using certain moulds. Such products are readily digestible, tasty and nutritious. Oncom is a popular dish of Indonesia and can be prepared by pressing the kernels to remove oil. Soak the cake in water for 24 h, drain and add with high starch material such as cassava or residue from soybean milk. Stem the material, incubate with fungus Neurospora intermedia or Rhizopus oligosporus and ferment for 1 to 2 days at 25 to 30°C after wrapping in banana leaves. It may be fried in oil or margarine and consumed. Fermented dough and kisra is prepared in the traditional way employed by the typical Sudanese housewife (Singh, 1992).
Tofu is popular groundnut product in China and Japan. Soaking the groundnut kernels overnight and grinding into an emulsion may prepare it. Boil the fine mash or steam and filtre it through a cloth. The curd may be precipitated from the resulting fluid by adding calcium or magnesium sulphate. The product is left to settle and transferred to boxes lined with cloth filtres or spread on trays. May be sold as slices or slabs, curd is served in soup; the wet curd can be deep fried in oil.
Groundnut cake meal or defatted meal, can be used to prepare bakery products (Table 18). Breads, biscuits, cookies and other products could be excellent vehicles for enhancing the utilization of groundnut protein in the diets of malnourished people in the developing countries.
Table 18. Acceptability of different bakery products prepared from wheat: groundnut meal blends.
|Control, 100% refined wheat flour||4.4||4.8||4.8||4.9||4.8|
|CD at 5%||0.70||0.64||0.66||0.54||0.74|
|SE value (±)||0.25||0.22||0.22||0.19||0.26|
|Acceptability was judged by the panellists for taste, flavour and appearance. Partially defatted flour. Completely defatted flour Score:|
Excellent=4 to 5, Good=3 to 4, Fair=2 to 3, Poor=1 to 2 and Very Poor=0 to 1.
Source: Kadam and Chavan, 1991, ICRISAT
Health-conscious consumers in the developed countries prefer low-fat groundnut that is now being sold under the trade name Weight Watchers®. A commercial process that squeezes out about 50 percent of the oil from raw groundnuts, which then regain their shape after being squeezed, makes low-fat groundnut. The groundnuts are then soaked in hot water and roasted in oil for 5 minutes. The water steaming out of the kernels prevents roasting oil from entering them resulting in a crunchy groundnut with 50 percent less fat than normal. This product may be prepared by the groundnut-producing countries for export to developed countries to earn valuable foreign exchange.
Groundnut is used to improve protein content and quality of several cereal-based food products in India, Kenya, Malawi, Nigeria, Senegal and Zimbabwe. In India alone, there have been several agriculture-product with groundnut as the protein-enriching medium. The partially defatted flour is used to improve the nutritional quality of various cereal-based products such as gonfa, millet (Pennisetum glaucum) based product and epo-ogi, a corn (Zea mays) based gruel. Uji is food product commonly prepared from maize or sorghum in Tanzania.
In Sudan groundnut cake after oil extraction is exported, kisra is sorghum-based food can be prepared to convert the groundnut cake into flour for local consumption. Acceptable and nutritionally superior quality kisra is prepared from sorghum flour fortified with defatted groundnut flour. The addition of defatted groundnut flour resulted in improvement of baking ease, colour and texture of the final product. The percentage increase in protein content at the 30 percent level of fortification varied from 53 percent to 122 percent. Fortification with groundnut and subsequent fermentation improves the in vitro digestibility of the sorghum flour (Singh 1991). A supplementation level of 20 percent is considered adequate to achieve the desired nutritive benefits. The proportion of total amino acids (T), which must be supplied as essential amino acids (E), the E/T ratio is considered as a quality index in the FAO Provisional Pattern (FAO/WHO Adhoc Expert Committee 1973). In developing countries where sorghum is a staple diet, there is a need to have a nutritional improvement programme on sorghum. Acceptable gari, a commonly used cassava-based Nigerian food, can be prepared with 15 percent defatted groundnut flour. There was a four-fold increase in the amount of protein at this level of fortification and a remarkable increase in the concentration of all amino acids was observed.
In India groundnut is used to prepare laddu and chikki. To prepare laddu, groundnut kernels are roasted and seed coat is removed, the separated cotyledons are mixed with thick, hot jaggery syrup. Small portions of the mixture are pressed by hand to obtain balls or laddus, about 3 to 5 cm in diameter. Chikki is very popular product in Western India. It is prepared by mixing roasted and decorticated groundnut kernels with hot slurry of sugar. The mixture is spread in a 1.0 to 1.5 cm thick layer on a tray or similar flat surface. After, cooling the product is cut into small pieces and packed. Roasted groundnuts are also used in the preparations of various other traditional recipes such as khichadi, guradani, barfi and vegetable curries, in India. Recently National Institute for Nutrition, Hyderabad, India has introduced a new sweet prepared by groundnut, jiggery and wheat floor with low fat and high energy, named Suruchi. The product is being tested on the school children for its calorific value and consumer acceptance. Such products may give food-nutritional security to the school going children in developing countries. Please see Figure 30.
The United Nations Development Programme (UNDP), in partnership with the Food and
Agriculture Organization of the United Nations (FAO), in collaborating with the Technology Mission on Oilseeds and Pulses Ministry of Agriculture, Government of India (GOI) have published a “Culinary Preparations with Groundnut”. The publication mentioned 42 delicious preparations with groundnut with the intent to promote groundnut as food crop for sustained nutritional security. Some important recipes are: groundnut curry, chow chow fry, groundnut omelette, groundnut vada, groundnut pakodi, groundnut chakkilam, groundnut halava and various chutneys with groundnut (Soluchana, et al., 2000).
Figure 30: Groundnut confectioneries.
Technologies are also available to prepare the following items from groundnuts: Yuba (groundnut film) a protein-lipid film, may be developed from groundnut milk, groundnutbased yoghurt, groundnut bars, chicken patties extended with groundnut flour, chocolateflavoured groundnut beverages, groundnut patties, tube feeding product containing groundnut protein, nutritious snacks for school-age children, groundnut nougat, fermented groundnut milk and groundnut sauces (Beuchat, et al., 1992).
Partially defatted groundnuts
This process involves removing the oil from the groundnuts and then reconstituting and roasting the kernels. It is interesting to note that the process was developed in the USA out of the quest for the low calorie product and not because of a need to get at the oil in groundnuts. Roasted groundnut kernels without skins generally contain 24 to 26 percent protein, 46 to 50 percent oil, 18 to 20 percent carbohydrates, 1.5 to 2.5 percent moisture and 2.5 to 3 percent ash. They also contain many essential minerals and vitamins. The defatting process removes up to 80 percent of the oil in groundnuts, thereby reducing the calorie content while still retaining the protein value. This process consists essentially of three simple mechanical operations: i.) pressing ii.) reconstitution and iii.) drying and roasting, either raw (with skin) or blanched groundnuts are hydraulically pressed to remove the desired amount of oil. The pressed de-shaped blanched groundnuts are heated in boiling water to expand them and to restore their original shape and size. Salt and other ingredients can be added during the expansion step. The expanded groundnuts are then dried and roasted with or without oil. Using a hydraulic press, it is possible to remove 80 percent of the oil from the groundnuts at a pressure of 2 000 psi in 50 minutes. In commercial operations both the cage pot presses are being used. Partially defatted groundnuts air-dried and roasted after 80 percent oil the oil removed. There is a little loss of taste, however defatted groundnuts become slightly harder than real roasted groundnuts. Research is needed to produce a softer product.
Synthetic fibres from groundnut proteins
The process developed for the manufacture of Ardil on a commercial scale is as follows: The protein is first extracted from blanched groundnuts with dilute alkali and it is precipitated again by the addition of acid or SO2 until the iso-electric range pH 5 is reached. The precipitated protein is again dissolved in dilute caustic soda so that a solution of 20 to 30 percent concentration of protein with an initial pH of at least 12.5 is obtained. The solution is allowed to mature for a certain period to attain the spinnable viscosity (between 50 to 5 000 poises). It is then extruded at a constant rate through a spinnerets into a coagulating bath containing 15 percent sodium soleplate and about 1 percent sulphuric acid at temperature 25°C to 40°C. At the end of this treatment the fibres are washed free from acid and salt. They are then adjusted to a pH of about 8 so that they will dye evenly with wool. The final product is a cream coloured crimped fibre with a soft wool-like feel.
Groundnut cake meal is also useful for the preparation of vegetable protein adhesives. Groundnut cake protein glue is already being used in the production of commercial plywood by some of the plywood factories in India. Ardein a commercial preparation of the groundnut rich in the globulin arachin when isolated and fed to milch cows has been found to increase milk production by 35 percent and fat production by 54.1 percent.
Groundnut protein film
Groundnut protein film is one of the alternative edible films that can be used in an intermediate moisture food (IMF) due to its promising characteristics: bland flavour, low oxygen permeability and its ability to incorporate antimicrobial agents. This study has provided information on possible use of peanut protein film with and without sorbic acid, as an edible coating for IMF. The predicted sorbic acid profile in coated food showed that groundnut protein might be used to retard sorbic acid migration from surface to food core and extend the product shelf life. Contrary to the expected result, the use of coating did not show any significant effect in delaying Salmonella aureus growth. A thin coating used may have attributed to this observed performance (Jangchud, et al., 1999).
Uses of groundnut shell
Of the several million tonnes of groundnut produced each year, hulls form about 25 percent of the total mass produced and their utilization thus becomes very important. At present in the developing countries the majority of groundnut hulls are either burned, dumped in forest areas or left to deteriorate naturally. Sufficient information is available to use groundnut hull in cattle feed, as carrier of insecticide, in the manufacture of logs and production of pulp and as a fibre component in human diet. Hull digestibility is quite low; research efforts are being directed to improve it as it contains more than 60 percent fibre. Inoculation and biodegradation of hull have been tried but these efforts have not been successful (Kerr, et al., 1986). The shell also used for the production of alpha-cellulose. By adopting the neutral sulphate method about 40 to 42 percent of unbleached pulp yield on an average 93 percent of alpha-cellulose from groundnut shell. Finely ground groundnut shells are often used for polishing tin plate.
Groundnut shell charcoal making
Charcoal making is based on the principle that groundnut shell can be converted into charcoal by incomplete burning. Limiting the amount of air used during the burning process produces incomplete burning. Thus, the quality and quantity of charcoal depend largely on how well the amount of air is regulated in the charcoal chamber. Groundnut shell can also be used for preparing activated carbon.
Tests have shown that dehydrated and pelleted groundnut vines is valuable by-product and are far superior to Bermuda grass particularly in digestible nutrients and possibly as a source of carotene.