The effects of environmental factors on fatty acid composition and the assessment of marbling in beef cattle: a review

Abstract

Marbling refers to the appearance of white flecks of fatty tissue between muscle fibre bundles. The whiteness and opacity of the fat is important for visual assessment of marbling and depends on the crystallisation of the triacylglycerols within the fat cells. In the living animal, fat is in a liquid state. With chilling, the triacylglycerols undergo phase changes (solidify) and become opaque. The temperature at which this occurs is largely dependent upon the melting points of the individual fatty acids. Marbling fat can comprise a diverse range of fatty acids and each has an individual melting point (e.g. palmitoleic melts at 0°C; stearic melts at 70°C). The visual appearance of marbling will thus depend on the melting points of the constituent fatty acids at chiller temperature. The high melting point stearic acid can vary significantly in content across groups of cattle and has a major influence on the physical properties and visual appearance of marbling fat. The effects of nutrition, seasonal and climatic variation are reviewed and linked to marbling appearance and fat hardness.

Survey of the fatty acid composition of Canadian beef: Backfat and longissimus lumborum muscle

“…Differences in SFA likely relate to climatic differences. Colder temperatures in winter increase^9-desaturase activity converting SFA to monounsaturated fatty acids (MUFA), which is required to maintain fat in a fluid state (Tume 2004). Colder temperatures in winter also increase rates of digesta passage from the rumen (Kennedy et al 1977), which may limit time available for biohydrogenation of PUFA to SFA.…”

Should animal fats be back on the table? A critical review of the human health effects of animal fat

“…If humans are to consume animal fat then the best quality fat should be produced (Kelly et al 2001;Tume 2004;Givens 2005;Shingfield et al 2013). This review suggests that this results in some clear selection and production/nutrition goals for animals.…”

Real-time ultrasound (RTU) imaging methods for quality control of meats

“…Before reviewing the use of ultrasound technology to examine these features, the differences between IMF and marbling should be outlined. IMF refers to the chemically extractable fat in a muscle (Shi-Zheng and Su-Mei, 2009) and is an objective measurement, whereas marbling, assessed visually, refers to the appearance of evenly distributed white flecks or streaks of fatty tissue between bundles of muscle fibres (Tume, 2004) and can be subjectively assessed with grading scores or objectively assessed when image analysis is used (e.g., Faucitano et al ., 2005;Jackman et al ., 2008). Both are relevant for meat quality evaluation and are closely related to each other (correlation coefficients of up to 0.8 in Savell et al ., 1986;Devitt and Wilton, 2001;Kemp et al ., 2002).…”