Latest News on Proximate Composition Research: Feb – 2020

Proximate composition of fish

1) Efforts over the past century to determine the proximate composition of fish are only partially successful, as many gaps in our knowledge still exist. 2) Large variations occur in proximate composition, both from species to species and also from fish to fish of an equivalent species. additionally , large variations occur in composition of various parts of the fish. 3) The protein content of fish, although averaging about 19 per cent, may vary from 6 to twenty-eight per cent. Oil content may vary from 0,2 to 64 per cent, ash from 0.4 to 1.5 per cent, and moisture from 28 to 90 per cent. 4) A classification into five categories with reference to oil and protein contents of fish is proposed. Most species fall under the category of low oil and high protein content. [1]

Factors affecting the proximate composition of cultured fishes with emphasis on salmonids

The endogenous and exogenous factors reported to affect the proximate composition of cultured fishes, with emphasis on salmonids, are examined. Methods of reporting and comparing proximate composition are discussed. Examination of measurements presented during a number of published papers, using allometric analysis, indicates that comparison of proximate compositions on a dry weight basis and failure to incorporate fish size as a covariate have, in many cases, led to erroneous conclusions concerning the consequences of environmental and dietary factors on the proximate composition of cultured fishes. Available evidence indicates that the protein content of growing salmonids is decided solely by fish size (is endogenously controlled), that lipid level is effected by both endogenous and exogenous factors, that ash content is homeostatically controlled, which whole body moisture is inversely associated with body lipid. [2]

Shellfish: proximate composition, minerals, fatty acids, and sterols.

Proximate composition, minerals, fatty acids, and sterols were determined for eight species of shellfish commonly marketed within the Northwest. Moisture and total lipid content varied with the dimensions of the species, with more variation in mollusca than in crustacea; total lipid content ranged from 0.7% in sea scallops to three .1% in blue mussels but only from 1.2% in Dungeness crab to 1.3% in pink shrimp. The mineral content was highly variable; the mineral content of Northwest samples attended be less than that reported in other studies. Generally, shellfish are good sources of zinc, and Pacific oysters, blue mussels, and Manila clams also are good sources of iron. Five fatty acids (16:0, 16:1, 18:1, 20:5n-3, and 22:6n-3) represented from 60% to 84% of the carboxylic acid content. hexadecanoic acid ranged from 13% to 32% of the entire fatty acids. Long-chain n-3 polyunsaturated fatty acids were predominant (37.6% to 54.3%), with sea scallops containing quite 50%; n-6 polyunsaturated fatty acids ranged from 1.5% to 6.5%. In crustacea, cholesterol was the first sterol, and brassicasterol was the sole other measurable sterol. [3]

Nutritional and antioxidant components and antioxidant capacity in green morph Amaranthus leafy vegetable

Amaranth has two morphological types described as red and green morphs. Previous studies have extensively characterised red morph amaranth regarding both morphological and chemical properties including antioxidant activity, antioxidant phytochemical profile, mineral content and proximate composition. However, there’s scarce information concerning green morph amaranth. Hence, this study evaluated 12 green morph genotypes for proximate composition, antioxidant activity, antioxidant pigments, minerals, and phytochemicals. Green morph amaranth was found to contain abundant carbohydrates, dietary fiber and protein. [4]

Changes in Proximate Composition of Corn Meal (Ogi) Assisted with Lactobacillus Species

Ogi also referred to as corn meal may be a carbohydrate rich food that forms the diets of most weaning infants and adults in some West African countries including Nigeria. The aim of this study was therefore to research the effect of Lactobacillus brevis and L. plantarum on the proximate composition of ogi. All analyses were administered using standard techniques. Fresh ogi was prepared from corn via selection, washing, steeping for two to three days, wet milling and sieving. L. plantarum and L. brevis were then inoculated into the corn meal and incubated anaerobically for twenty-four hours at 37°C. Following inoculation, the proximate compositions of the control and Lactobacillus species inoculated samples were determined. On enrichment with L. brevis and L. plantarum, the protein, fat, ash, crude fibre, and moisture contents were significantly increased (p < 0.05) while carbohydrate was lowered after fermentation. [5]

Reference

[1] Stansby, M.E., 1962. Proximate composition of fish. (Web Link)

[2] Shearer, K.D., 1994. Factors affecting the proximate composition of cultured fishes with emphasis on salmonids. Aquaculture, (Web Link)

[3] King, I., Childs, M.T., Dorsett, C., Ostrander, J.G. and Monsen, E.R., 1990. Shellfish: proximate composition, minerals, fatty acids, and sterols. Journal of the American Dietetic Association, (Web Link)

[4] Nutritional and antioxidant components and antioxidant capacity in green morph Amaranthus leafy vegetable
Umakanta Sarker, Md. Motaher Hossain & Shinya Oba
Scientific Reports, (Web Link)

[5] O. Edet, U., U. B. Ebana, R., U. Okoro, C., M. Ekanemesang, U., M. Ikon, G., W. Ntukidem, N. and M. Uduak, E. (2017) “Changes in Proximate Composition of Corn Meal (Ogi) Assisted with Lactobacillus Species”, Journal of Advances in Microbiology, (Web Link)

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