UMR 1253 Science et Technologie du Lait et de l'Œuf, Inra-Agrocampus Rennes, 65 rue de St-Brieuc, 35042 Rennes Cedex, France; Agrocampus Ouest, 65 rue de St-Brieuc, 35042 Rennes Cedex, France; Faculté d'Agronomie et des Sciences de l'Environnement, Université Dandicko Dankoulodo de Maradi, BP 465 ADS Maradi, Niger.
UMR 1253 Science et Technologie du Lait et de l'Œuf, Inra-Agrocampus Rennes, 65 rue de St-Brieuc, 35042 Rennes Cedex, France; Agrocampus Ouest, 65 rue de St-Brieuc, 35042 Rennes Cedex, France.
Food Res Int. 2018 Mar;105:694-702. doi: 10.1016/j.foodres.2017.11.056. Epub 2017 Nov 23.
Milk is often subjected to technological treatments which have impacts on the structure of milk constituents and the characteristics of rennet curds. In this paper, the influence of the dairy fat structure on the biochemical and textural characteristics of curds coagulated by an extract of Calotropis procera leaves was studied. Standardized milks were reconstituted with the same contents in protein (35g·kg) and fat (35g·kg) but with different structures of fat i.e. homogenized anhydrous milk fat (HAMF), homogenized cream (HC) and non-homogenized cream (NHC). As expected, the size distributions of fat globules in the different milks were different. After their coagulations by the plant extract, the physico-chemical characteristics of the curds and respective wheys were determined. No difference was observed in the coagulation time between the three milks but the whey removed more quickly from HAMF and HC curds than NHC-curd. The biochemical analyses of curds revealed a lower content in dry matter and fat in the NHC-curd compared to HAMF- and HC-curds. Otherwise, the NHC-whey exhibited the highest amount of fat. Observations by confocal microscopy showed that the fat globules were homogenously distributed and well trapped in the protein networks of HAMF- and HC-curds. In the NHC-curd, the fat globules were located in whey pockets, with less connectivity with the protein network. The textural analysis showed that the NHC-curd was more elastic, soft and adhesive than HAMF- and HC-curds. Homogenization significantly reduced the loss of fat during cheese manufacturing and conferred specific textural characteristics to the curds coagulated by an extract of Calotropis procera.
牛奶经常经过技术处理，这些处理会影响牛奶成分的结构和凝乳酶凝乳的特性。在本文中，研究了乳脂结构对用 Calotropis procera 叶提取物凝结的凝乳的生化和质构特性的影响。用相同含量的蛋白质（35g·kg）和脂肪（35g·kg）重新配制标准化牛奶，但脂肪结构不同，即均化无水乳脂（HAMF）、均化奶油（HC）和非均化奶油（NHC）。如预期的那样，不同牛奶中的脂肪球大小分布不同。在用植物提取物凝结后，测定了凝乳和各自乳清的物理化学特性。三种牛奶的凝结时间没有差异，但 HAMF 和 HC 凝乳的乳清去除速度快于 NHC 凝乳。凝乳的生化分析表明，NHC 凝乳中的干物质和脂肪含量低于 HAMF 和 HC 凝乳。另一方面，NHC 乳清中含有最多的脂肪。共聚焦显微镜观察表明，脂肪球均匀分布并很好地被 HAMF 和 HC 凝乳中的蛋白质网络捕获。在 NHC 凝乳中，脂肪球位于乳清袋中，与蛋白质网络的连接较少。质构分析表明，与 HAMF 和 HC 凝乳相比，NHC 凝乳更具弹性、柔软和粘性。均质化显著减少了奶酪生产过程中脂肪的损失，并赋予了用 Calotropis procera 叶提取物凝结的凝乳特定的质构特性。
