Condensed milk storage and evaporation affect the flavor of nonfat dry milk
Condensed milk storage and evaporation affect the flavor of nonfat dry milk
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DOI：
10.3168/jds.2016-11530
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发表时间：
2016-12-01
影响因子：
3.5
通讯作者：
Drake, MaryAnne
中科院分区：
文献类型：
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作者：
Park, Curtis W.;Drake, MaryAnne
脱脂奶粉 (NFDM) 制造中的单元操作会影响感官特性，从而影响其在配料应用中的使用和接受度。由于运输或缺乏干燥能力，在喷雾干燥之前，脱脂炼乳可能会在冷藏温度下储存很长时间。目前，NFDM 加工商有 2 种将牛奶浓缩至固体含量高达 30% 的选项：蒸发 (E) 或反渗透 (RO)。本研究的目的是确定炼乳储存和牛奶浓缩方法（E 与 RO）对 NFDM 风味的影响，并研究风味差异背后的机制。对于实验 1，脱脂奶进行巴氏灭菌并通过 E 或 RO 浓缩至 30% 固体，然后在 4°C 下储存 24 小时或通过 E 浓缩至 50% 固体并立即喷雾干燥。为了研究实验 1 结果背后的机制，构建了实验 2。在实验2中，对巴氏灭菌脱脂奶进行4种处理中的一种：对照（无E），在无真空的蒸发器中加热，E浓度为30%固体，或E浓度为40%固体。然后将奶稀释至相同的固体含量并进行评估。在蒸发器的蒸汽分离器中浓缩期间还测量了挥发性化合物。通过描述性感官分析评估感官特性，并进行仪器挥发性化合物分析以评估挥发性化合物。研究了储存和浓缩方法之间的相互作用。在实验 1 中，与 RO 相比，E 降低了 NFDM 中的甜味芳香风味和许多特征性牛奶风味化合物，并增加了纸板风味和熟食风味。液体储存增加了纸板风味以及己醛和辛醛，并降低了甜味芳香风味和香草醛浓度。实验 2 的结果表明，由于浓缩过程中施加的热量和真空，蒸发器中的蒸汽分离器去除了特有的牛奶风味及其相关的挥发性化合物。这些结果表明，当使用 RO 代替 E 并避免储存炼乳时，异味会显着减少。
Unit operations in nonfat dry milk (NFDM) manufacture influence sensory properties, and consequently, its use and acceptance in ingredient applications. Condensed skim milk may be stored at refrigeration temperatures for extended periods before spray drying due to shipping or lack of drying capacity. Currently, NFDM processors have 2 options for milk concentration up to 30% solids: evaporation (E) or reverse osmosis (RO). The objective of this study was to determine the effect of condensed milk storage and milk concentration method (E vs. RO) on the flavor of NFDM and investigate mechanisms behind flavor differences. For experiment 1, skim milk was pasteurized and concentrated to 30% solids by E or RO and then either stored for 24 h at 4 degrees C or concentrated to 50% solids by E and spray dried immediately. To investigate mechanisms behind the results from experiment 1, experiment 2 was constructed. In experiment 2, pasteurized skim milk was subjected to 1 of 4 treatments: control (no E), heated in the evaporator without vacuum, E concentration to 30% solids, or E concentration to 40% solids. The milks were then diluted to the same solids content and evaluated. Volatile compounds were also measured during concentration in the vapor separator of the evaporator. Sensory properties were evaluated by descriptive sensory analysis and instrumental volatile compound analysis was conducted to evaluate volatile compounds. Interaction effects between storage and method of concentration were investigated. In experiment 1, E decreased sweet aromatic flavor and many characteristic milk flavor compounds and increased cardboard and cooked flavors in NFDM compared with RO. Liquid storage increased cardboard flavor and hexanal and octanal and decreased sweet aromatic flavors and vanillin concentration. Results from experiment 2 indicated that the 'characteristic milk flavors and their associated volatile compounds were removed by the vapor separator in the evaporator due to the heat and vacuum applied during concentration. These results demonstrate that off -flavors are significantly reduced when RO is used in place of E and storage of condensed milk is avoided.