Abstract
This study was undertaken to evaluate the eating quality of longissimus thoracis steaks and hamburgers (80/20 gluteus medius to perirenal fat) with enhanced profiles of potentially healthy fatty acids. The profile of health favorable fatty acids (n-3, vaccenic and rumenic) was improved in beef by feeding co-extruded flaxseed (flaxseed, peas, and alfalfa) and alfalfa-grass hay as a total mixed ration (TMR), and further enhanced by feeding co-extruded flaxseed before alfalfa-grass hay (Non-TMR). Compared to TMR, feeding steers the Non-TMR resulted in tougher steaks (P < 0.05) with lower beef flavor (P < 0.01) and greater off-flavor (P < 0.01) intensity to an extent that might be detectable by consumers. High levels of trans-monounsaturated fatty acids, mainly of vaccenic acid, were associated with a fishy off-flavor, although actual changes in flavor may relate to correlated combined effects of conjugated fatty acids, atypical dienoic acids and ɑ-linolenic acid. Diet had no significant effect on sensory attributes of hamburgers, but when panelists described off-flavors, they noted more ‘other’ off-flavors (P < 0.05) with fishy and stale/cardboard notes being more prominant in Non-TMR hamburgers. Overall, beef samples with threshold levels of vaccenic acid over 6.12% of total fatty acids resulting from feeding flaxseed products, while of potentially greater health benefit, may pose challenges in terms of eating quality. Areas worthy of further investigation to ensure acceptable eating quality might be the influence of ageing on antioxidant capacity in beef with enhanced fatty acid profiles, and the potential use of protective packaging to limit deterioration.
Highlights
IntroductionQuality and price are considered key factors (Realini et al, 2014)
When consumers purchase beef, quality and price are considered key factors (Realini et al, 2014)
Microbial lipases bind to dietary lipids present in the rumen and release free fatty acids such as polyunsaturated fatty acids (PUFA), which are toxic to rumen microbes (Jenkins et al, 2008)
Summary
Quality and price are considered key factors (Realini et al, 2014). An increasing number of informed consumers from medium to high incomes are factoring in the health implications of beef consumption to their meat purchases (Kallas et al, 2014; Realini et al, 2014). PUFA are biohydrogenated by the rumen microbes, producing saturated fatty acid (SFA) of lower toxicity, 18:0. The residual PUFA biohydrogenation intermediates (PUFA-BHI) originated during this process bypass the rumen, and are absorbed from the lower gut and incorporated into tissues, including muscle (Scollan et al, 2014). Beef can be a source of PUFA-BHI, including t11–18:1 (vaccenic acid) and c9,t11–18:2 (rumenic acid), which may have beneficial health effects related to cancer, inflammatory
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