School of Applied Sciences, AUT Univ, Private Bag 92006, Auckland 1142, New Zealand.
J Food Sci. 2012 Feb;77(2):S122-7. doi: 10.1111/j.1750-3841.2011.02557.x. Epub 2012 Feb 6.
Goat milk fat includes several branched chain fatty acids (BCFAs), like 4-methyloctanoic acid, which when free, are responsible for goaty flavor. This flavor limits the market opportunities for goat milk. Prior research showed that cyclodextrins (CDs) can reduce goaty flavor, presumably by binding free fatty acids. This research extends that observation. In odor ranking trials in citrate buffer at pH 4.8, β-CD concentrations between 0% and 0.35% were increasingly effective in reducing odor intensity due to 4-methyloctanoic acid, but only when present in high molar excess. α-CD was also effective, but γ-CD was not. In lipase-treated goat milk only β-CD was effective but at much lower molar excess, a difference potentially explained by several factors. One was that BCFAs bind to CDs in marked preference to their straight chain isomers. Displacement experiments with phenolphthalein disproved that hypothesis. The ability of β-CD to reduce goaty flavor intensity extended to yogurt. An analytical panel showed that flavor of goat yogurt was reduced by addition of β-CD, but only if added before heating and fermentation. A hedonic trial showed that consumers preferred unsweetened and sweet/vanilla-flavored goat yogurt more when β-CD was included, P = 0.004 and 0.016, respectively. Males liked all yogurts more than females (P < 0.01), but there was a treatment × gender interaction (P = 0.016) for sweet/vanilla yogurt: sweet/vanilla masked the goaty flavor for males but not females. This results parallels previously demonstrated gender effects for sheepmeat flavor caused by BCFAs.
β-Cyclodextrin masks goaty flavor in yogurt, and with its GRAS status means it could be used in commercial goat yogurts and similar products so the real or perceived nutritional advantages of goat milk are not lost to goaty flavor.
羊奶脂肪包含几种支链脂肪酸（BCFAs），如 4-甲基辛酸，游离时会产生羊奶味。这种味道限制了羊奶的市场机会。先前的研究表明，环糊精（CDs）可以通过结合游离脂肪酸来减少羊奶味。这项研究扩展了这一观察结果。在 pH 值为 4.8 的柠檬酸盐缓冲液中的气味排序试验中，β-CD 的浓度在 0%至 0.35%之间，由于 4-甲基辛酸的存在，其降低气味强度的效果逐渐增强，但前提是存在高摩尔过量。α-CD 也有效，但 γ-CD 无效。在经过脂肪酶处理的羊奶中，只有 β-CD 有效，但摩尔过量要低得多，这一差异可能有几个因素解释。一个因素是，BCFAs 与 CDs 的结合明显优先于它们的直链异构体。用酚酞进行的置换实验否定了这一假设。β-CD 降低羊奶味强度的能力扩展到酸奶。一个分析小组表明，添加 β-CD 可降低羊奶酸奶的风味，但前提是在加热和发酵前添加。一项愉悦试验表明，消费者更喜欢添加 β-CD 的无糖和甜/香草味羊奶酸奶，P 值分别为 0.004 和 0.016。男性比女性更喜欢所有酸奶（P<0.01），但对于甜/香草酸奶，存在处理×性别交互作用（P=0.016）：对于男性，甜/香草掩盖了羊奶味，但对于女性则不然。这一结果与先前证明的 BCFAs 对羊肉味的性别影响相吻合。
β-环糊精掩盖了酸奶中的羊奶味，而且由于其 GRAS 地位，它可以用于商业羊奶酸奶和类似产品中，因此羊奶的真正或感知到的营养价值不会因为羊奶味而丧失。
