Impact of Brassica and Lucerne Finishing Feeds and Intramuscular Fat on Lamb Eating Quality and Flavor. A Cross-Cultural Study Using Chinese and Non-Chinese Australian Consumers.

Use of forage brassicas (Brassica napus) and lucerne (alfalfa; Medicago sativa) as ruminant feeds has been linked to unacceptable flavors in sheepmeat. Lambs from low and high intramuscular fat sires were allocated to one of four finishing feeds-perennial ryegrass (Lolium perenne), lucerne, and two brassica forages-for a 6 week period. Grilled loins (Longissimus thoracis et lumborum) were subjected to chemical and sensory analysis by a trained panel and also evaluated by non-Chinese and Chinese background Australian consumers. Consumer liking was similar for both groups, and liking was highest for the brassica- and lucerne-finished lamb, especially from high intramuscular fat sires. No evidence of a distinctive lucerne- or brassica-induced flavor taint was measured by the trained panel or gas chromatography-mass spectrometry-olfactometry. The diets influenced the composition of lipids and branched-chain fatty acids in the subcutaneous fat, and the concentration of total branched-chain fatty acids was positively correlated with flavor and overall liking. Significantly higher levels of key aroma volatiles were measured in the higher fat samples.

Sensory and Flavor Chemistry Characteristics of Australian Beef: Influence of Intramuscular Fat, Feed, and Breed.

The sensory attributes and flavor chemistry of grilled beef striploins (M. longissimus lumborum, n = 42) varying widely in marbling from commercial production types typical for Southern Australia were extensively characterized. Striploins from Angus grass-fed yearlings (5.2-9.9% intramuscular fat), Angus grain-finished steers (10.2-14.9%), and Wagyu grass-fed heifers (7.8-17.5%) were evaluated. Inherent differences between samples from grass- and grain-fed Angus cattle were minimal when the intramuscular fat content was above ∼5%. After adjusting for intramuscular fat, Wagyu samples had more intense flavor and higher tenderness and juiciness compared to Angus grass-fed samples. Grilled beef flavor, dairy fat, and sweetness increased with the marbling level, and sourness and astringency decreased. Tenderness and juiciness increased with the marbling level and were correlated with Warner-Bratzler peak force measurements. Trained panel sensory differences in flavor corresponded with increases in aroma volatiles and changes in nonvolatile flavor compounds. Unsaturated fatty acids with potential health benefits (vaccenic, oleic, and rumenic acids) increased with the level of marbling.

Characterisation of taste-active extracts from raw Brassica oleracea vegetables.

Chemical and sensory characterisation of whole and fractionated myrosinase-free extracts from selected Australian-grown, raw Brassica vegetables (broccoli, cauliflower, Brussels sprouts and red cabbage) was carried out to determine the contribution of key phytochemicals (i.e. glucosinolates, free sugars, phenolics) to the taste profiles of these vegetables. Glucosinolate (GS) and phenolic profiles were determined by liquid chromatography coupled with photodiode array detection and mass spectrometry. Ten glucosinolates (GS) were quantified across the vegetables investigated. Brussels sprouts (186.3 µg g(-1) FW) followed by broccoli (164.1 µg g(-1) FW) were found to contain the most GS. The phenolic profiles of all samples were dominated by hydroxycinnamic acid derivatives. As expected, red cabbage was the only vegetable with a significant anthocyanin signal (574.0 µg g(-1) FW). Red cabbage (26.7 mg g(-1) FW) and cauliflower (18.7 mg g(-1) FW) were found to contain a higher concentration of free sugars than Brussels sprouts (12.6 mg g(-1) FW) and broccoli (10.2 mg g(-1) FW). Descriptive sensory analysis of the whole extracts found sweetness (cauliflower and red cabbage sweeter than broccoli and Brussels sprouts) and bitterness (Brussels sprouts more bitter than others) as the most discriminating attributes. A hydrophilic fraction with sweetness, umami and saltiness as the main attributes was the most taste active fraction across all Brassica whole extracts. Sub-fractionation showed that this fraction was also bitter but the presence of sugars counteracted bitterness. Several components within each extract were found to contribute to the bitterness of whole Brassica extracts. The total and individual GS content alone could not explain the perceived bitterness of these extracts. Phenolics and/or other components are likely to be contributing to the bitterness associated with these vegetables.