Laboratory methods for sensory analysis of food : Part 5

Okra (Abelmoschus spp.) is a traditional vegetable crop with considerable area under cultivation in Africa and Asia with huge socio-economic potential in West and Central Africa. It has been called “a perfect villager’s vegetable” because of its robust nature, dietary fibers and distinct seed protein balanced in both lysine and tryptophan amino acids (unlike the proteins of cereals and pulses) it provides. However, okra has been considered a minor crop and no attention was paid to its improvement in the international research program in past. This review describes a general overview of okra’s nutritional and economic potential with special reference to its past and recent progress on germplasm regeneration, genetic studies and efforts on genetic improvement in West and Central Africa.

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Okra (Abelmoschus spp.) in West and Central Africa: Potential and progress on its improvement

Rheological characterization of okra pectins

Bambara groundnut (Vigna subterraenea (L.) verdc) (BGN) is a legume; its origin have been traced back to Africa, and it is the third important legume; however, it is one of the neglected crops. It is highly nutritious, and has been termed a complete food. Its seed consist of 49%-63.5% carbohydrate, 15%-25% protein, 4.5%-7.4% fat, 5.2%-6.4% fiber, 3.2%-4.4% ash and 2% mineral compared to whole fresh cow milk 88% moisture, 4.8% carbohydrate, 3.2% proteins, 3.4% fat, 0.7% ash, and 0.01% cholesterol. Its chemical composition is comparable to that of soy bean. Furthermore, BGN has been reported to be a potential crop, owing to its nutritional composition, functional properties, antioxidant potential, and a drought resistant crop. Bambara groundnut milk (BGNM) had been rated higher in acceptability than milk from other legumes like soybean and cowpea. Probiotics have been defined as live microorganisms which when administered in adequate amount confer a health benefit on the host. These benefits have been reported to be therapeutic, suppressing the growth and activity in conditions like infectious diarrhea, irritable bowel syndrome, and inflammatory bowel disease. The nutritional profile of BGNM is high enough to sustain the growth of probiotics. BGNs are normally boiled and salted, eaten as a relish or roasted, and eaten as a snack. Hence, BGNM can also be fermented with lactic acid bacteria to make a probiotic beverage that not only increase the economic value of the nutritious legume but also help in addressing malnutrition.

http://digitalknowledge.cput.ac.za/bitstream/11189/8219/1/Potential%20of%20Bambara%20Groundnut%20%28Vigna.pdf

Potential of Bambara Groundnut (Vigna subterranea (L.) Verdc) milk as a probiotic beverage—A Review

Okra ( Abelmoschus esculentus) is an economically important vegetable crop grown in tropical and sub-tropical parts of the world. This paper was aimed to review nutritional quality and potential health benefits of edible parts of Okra. Okra is a multipurpose crop due to its various uses of the fresh leaves, buds, flowers, pods, stems and seeds. Okra immature fruits, which are consumed as vegetables, can be used in salads, soups and stews, fresh or dried, fried or boiled. It offers mucilaginous consistency after cooking. Often  the  extract  obtained  from  the  fruit  is  added  to different  recipes  like stews  and  sauces  to  increase the  consistency.  Okra mucilage has medicinal applications when used as a plasma replacement or blood volume expander. The mucilage of okra binds cholesterol and bile acid carrying toxins dumped into it by the liver. Okra seeds are a potential source of oil, with concentrations varying from 20% to 40%, which consists of linoleic acid up to 47.4%. Okra seed oil is also a rich source of linoleic acid, a polyunsaturated fatty acid essential for human nutrition. Okra has been called “a perfect villager’s vegetable” because of its robust nature, dietary fiber, and distinct seed protein balance of both lysine and tryptophan amino acids. The amino acid composition of okra seed protein is comparable to that of soybean and the protein efficiency ratio is higher than that of soybean and the amino acid pattern of the protein renders it an adequate supplement to legume or cereal based diets. Okra seed is known to be rich in high quality protein especially with regards to its content of essential amino acids relative to other plant protein sources. Okra is a powerhouse of valuable nutrients, nearly half of which is soluble fibre in the form of gums and pectins which help to lower serum cholesterol, reducing the risk of heart diseases. The other fraction of Okra is insoluble fibre, which helps to keep the intestinal tract healthy. Okra is also abundant with several carbohydrates, minerals  and vitamins, which plays a vital role in human diet and health. Okra is rich in phenolic compounds with  important biological properties like quartering and flavonol derivatives, catechin oligomers and hydroxycinnamic  derivatives. Okra is also known for being high in antioxidants activity. Okra has several potential health beneficial  effects on some  of  the  important  human diseases like cardiovascular disease, type 2 diabetes, digestive diseases and some cancers. Overall, Okra is an important  vegetable  crop with a diverse  array of nutritional quality and potential health benefits. Key words : Okra, Nutritional, Quality, Health, Edible, Oil

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Nutritional Quality and Health Benefits of Okra (Abelmoschus esculentus): A Review

Chemical composition and the antioxidative properties of Nigerian Okra Seed (Abelmoschus esculentus Moench) Flour.

The drying kinetics of pineapple was studied, and the model that best describes it was selected. Pineapple slices were dried in a hot-air oven at temperatures of 50, 60 and 70C; microwave power levels of 385, 540 and 700 W, respectively; and under direct sunlight. Drying time decreased with increase in drying temperature and power level. Drying took place entirely in the falling rate-drying period. Seven mathematical models were fitted into the experimental data. The goodness of fit was determined using the coefficient of determination (R2), reduced chi-square (χ2), root mean square error and sum square error. The two-term, parabolic and Page model best explained the hot-air, microwave and sun-drying behavior of the pineapple. The effective moisture diffusivity increased from 6.89 × 10−10 to 5.1 × 10−08 m2/s while the activation energy was 12.46 KJ/mol for oven drying and 1.54 W/g for microwave drying.



Practical Applications

Pineapple as a fruit is a very rich source of minerals and vitamins including potassium, manganese, copper, magnesium, vitamin C and B6, thiamine, foliate, and also dietary fiber. These mineral and vitamins are essential for proper human growth and development especially for people who live on low income in tropical developing countries. The high moisture content of pineapple, which makes it highly perishable, and its abundance during periods of harvest, gives rise to postharvest losses with attendant reduction in the availability of its minerals and vitamins. Drying, a common preservative method, can be used to reduce these postharvest losses and thus make shelf-stable products last longer. The knowledge of the drying kinetics and subsequently the selection of an appropriate thin-layer drying model can be used to predict drying times and subsequently optimize the drying process for greater efficiency.

Mathematical Modeling of Thin‐Layer Pineapple Drying

Influence of pre-treatment on yield chemical and antioxidant properties of a Nigerian okra seed (Abelmoschus esculentus moench) flour.

The thin layer drying behaviour of ginger slices in a laboratory dryer was examined. The slices of 5 mm, 10 mm and 15 mm thicknesses were dried using heated ambient air at temperatures from 40 to 70 oC and air velocity of 1.5 m/s. The effects of drying air temperature and slice thickness on the drying characteristics, drying time and energy requirement of drying process was determined. The results have shown that an increase in the drying air temperature causes shorter drying times. Thinner slices also causes a shorter drying time. The effective moisture diffusivity values increased from 3.36814 × 10-10 m2/s to 5.82524 × 10-9 m2/s while the activation energy values for different slice thickness of ginger varied from 196.15 to 198.79 kJ/mol. The total needed energy varied from 735.3 to 868.5 kWh while the value of specific energy requirement varied from 3676.6 to 4342.4 kWh/kg respectively.

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Influence of Drying Conditions on the Effective Moisture Diffusivity and Energy Requirements of Ginger Slices

Various secondary metabolites such as essential oils (EOs) are produced by plants which, when extracted and concentrated, find their application in pharmaceutical, sanitary, cosmetic, agricultural, and food industries. There is an increasing interest in natural products, intended not only to delay/prevent the onset of chronic degenerative diseases, but also to prevent the deterioration of fats and other constituents of foodstuffs. EOs have been identified as natural food additives which can find useful application in food preservation. The objective of this chapter is to briefly describe the potential usage of EO in food preservation.

O.J. Oyelade

Papers

Chemical composition and the antioxidative properties of Nigerian Okra Seed (Abelmoschus esculentus Moench) Flour.

Mathematical Modeling of Thin‐Layer Pineapple Drying

Influence of pre-treatment on yield chemical and antioxidant properties of a Nigerian okra seed (Abelmoschus esculentus moench) flour.

Influence of Drying Conditions on the Effective Moisture Diffusivity and Energy Requirements of Ginger Slices

Use of Essential Oils in Food Preservation