European Journal of Food Science and Technology (EJFST)

EA Journals

Anti – Nutrients

Chemical Composition of Some Selected Fruit Peels (Published)

Global fruit production has experienced a remarkable increase. In 2011, almost 640 million tonnes of fruits were gathered throughout the world. In some fruits, peels represent almost 30% of the total weight and are the primary by-product. This study aims to investigate the chemical composition of fruit peels of some selected fruits. Peels of eight fresh fruits (orange, watermelon, apple, pomegranate, pawpaw, banana, pineapple and mango) were removed and analyzed for their nutrients and anti-nutrients contents. The results showed that lipid, protein, ash, crude fiber and carbohydrates contents in fruit peels were respectively from 3.36 ± 0.37 to 12.61 ± 0.63%, from 2.80 ± 0.17 to 18.96 ± 0.92%, from 1.39 ± 0.14 to 12.45 ± 0.38%, from 11.81 ± 0.06 to 26.31 ± 0.01% and from 32.16 ± 1.22 to 63.80 ± 0.16%. The minerals composition of fruit peels was respectively from 8.30 ± 0.54 to 162.03 ± 7.54 mg/100g for calcium, 0.66 ± 0.06 to 6.84 ± 0.55 mg/100g for zinc, 9.22 ± 0.63 to 45.58 ± 2.37 mg/100g for iron and 0.52 ± 0.10 to 9.05 ± 0.34 mg/100g for manganese. Concerning anti-nutrients, oxalates, hydrogen cyanides, phytates and alkaloids levels in fruit peels were within the threshold value reported as safety limit. The phenolics content of fruit peels ranged from 0.91 ± 0.06 to 24.06 ± 0.89%. Due to the proven health benefits of phenolic compounds, peels of these fruits can be used as good ingredients in formulation of health benefits food products.

Keywords: Anti – Nutrients, Fruit peels, Nutrients, Phenolic Compounds

Mineral and Antinutrients of Fresh and Squeezed-Washed Bitter Leaf (Vernonia Amygdalina) As Affected By Traditional De-Bittering Methods (Published)

The effect of traditional de-bittering methods on the mineral and anti-nutrient components of fresh and squeezed-washed bitter leaf was studied. Palm oil, Potash, Salt and boiling process was used in the squeeze-washing at 3 pre-processing methods of squeeze-wash and periods of 3 to 8 minutes. The percentage retention and losses of mineral and anti-nutrients increased simultaneously during squeeze-washing. Copper, magnesium, calcium and anti-nutrient had retention of 55 to 100% for samples squeezed-washed with palm oil than the other squeeze- washed samples. This could be due to rigidity of the cells which did not allow much nutrients to leach into the squeezed leaf-water. Loss of minerals and anti-nutrients was observed to be influenced directly by the cause-and-effect of disintegration changes which usually leads to softening due to the severity of the squeeze-washing on the bitter leaf instead of cellular composition or level of minerals and anti-nutrients initially present. Palm oil should be used in the squeeze-washing of bitter leaf for better nutrient retention.

Keywords: Anti – Nutrients, Bitter Leaf, De-Bittering, Mineral, Squeeze-Washing

Effect of Processing On the Nutritional and Anti Nutritional Properties of Canavalia Plagiosperma Piper Seeds (Published)

The effect of heat processing on the nutritional and anti nutritional qualities of oblique -seeded jack bean (Canavalia plagiosperma piper) was studied. Raw seeds of Canavalia plagiosperma (Oblique seeded Jack bean) were autoclaved (at 1210C, 15lb for 25, 30 and 35 minutes) and cooked (at 1000C for 30, 40 and 50 minutes). The proximate composition and anti-nutrients of the processed and raw samples were determined. The proximate composition showed that moisture content of raw seed was 8.26%, 35 minutes autoclaving increased it to 8.53% while 50 minutes cooking increased it to 8. 84%. Autoclaving reduced protein content from 31.54% to 31.28% while cooking reduced it from 31.54% to 28.86%. The ash content was reduced from 3.17% to 2.95% by autoclaving and from 3.17% to 2.51% by cooking. Autoclaving showed increasing effect on fat and energy content,(0.82-9.23%) and (1635.66-1637.94 KJ/g) respectively. The fibre content of the raw seed was found to be 0.94%, which was reduced to 0.88% by autoclaving and 0.62% by cooking. Cooking significantly increased the carbohydrate content (47.36-52.15%). The processing treatments showed significant effect (P≤0.05) on each parameter. Six (6) anti-nutrients (Saponin: 2.45%, Phytic acid: 3.15%, Tannin: 1.02%, Oxalate: 1.48%, Phenol: 0.34%, Trypsin Inhibitor: 11.53Tu/g) were determined in the raw seed. The six processing treatments given to the seed showed a general reduction trend on these six anti-nutrients at different rates and levels. From the results in Table 3 and 4, autoclaving was the best processing method for phytic acid, and phenol while cooking was the best processing method for tannin, trypsin inhibitor, saponin and oxalate.

Keywords: Anti – Nutrients, Canavalia plagiosperma piper, Proximate, autoclaving, cooking


African oak is one of the underutilized legumes in Nigeria. Information on various parts of this legume is required to enhance its utilization in foods and food products. Feeding of fowls with the flour made from the aril cap of the seed showed no harmful effect on them. The flour was then analyzed for chemical properties. Proximate analysis showed that the cap was appreciable in protein (5.69%), fat (18.5%), carbohydrates (63.91%), and fibre (5.4%) but low in ash (1.5%). The value of each of the anti – nutrients analyzed was below the lethal level. Although the cap was found to be low in ash content, it had appreciable amounts of some essential elements. These are sodium (7.10±1.00), potassium (148.0±0.10), calcium (7.02±0.00), magnesium (109.12±1.02 ppm), phosphorus (11.20±1.10 ppm), and iron (0.25±0.02mg/g).The vitamin components of the cap determined were A (234.7±0.00µg/g), C (4.0±1.00mg/100g), E (1.1±0.02mg/100g) and the B – vitamins; B1, B2, B6 and B12 (2.0±1.01, 33.0±0.11, 4.3±1.00 and 4.8±0.10)mg/100g, showing good amounts of the vitamins. Due to high proximate, vitamins, minerals and insignificant anti – nutrient compositions of the aril cap of the African oak seed, it could be used in both human and animal foods. There is therefore a need for food industries and feed formulators to utilize the cap.

Keywords: African Oak, Anti – Nutrients, Minerals, Proximate, Vitamins

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