Felix da Silva Denise, Matumoto-Pintro Paula T, Bazinet Laurent, Couillard Charles, Britten Michel
Departamento de Agronomia, Universidade Estadual de Maringá, Avenida Colombo 5790, Maringá, Paraná 87020-900, Brazil.
Dairy Research Centre (STELA), Université Laval, Quebec City, Quebec, Canada G1V 0A6; Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec City, Quebec, Canada G1V 0A6.
J Dairy Sci. 2015 Mar;98(3):1552-62. doi: 10.3168/jds.2014-8796. Epub 2015 Jan 15.
Grape extracts can be added to milk to produce cheese with a high concentration of polyphenols. Four commercial extracts from whole grape, grape seed, and grape skin (2 extracts) were characterized and added to milk at concentrations of 0, 0.1, 0.2, and 0.3% (wt/vol). The effect of grape extracts on the kinetics of milk clotting, milk gel texture, and syneresis were determined, and model cheeses were produced. Whole grape and grape seed extracts contained a similar concentration of polyphenolic compounds and about twice the amount found in grape skin extracts. Radical scavenging activity was directly proportional to the phenolic compounds content. When added to milk, grape extracts increased rennet-induced clotting time and decreased the clotting rate. Although differences were observed between the extracts, the concentration added to milk was the main factor influencing clotting properties. With increasing concentrations of grape extracts, milk gels showed increased brittleness and reduced firmness. In addition, syneresis of milk gels decreased with increasing concentrations of grape extracts, which resulted in cheeses with a higher moisture content. The presence of grape extracts in milk slightly increased protein recovery in cheese but had no effect on fat recovery. With whole grape or grape seed extracts added to milk at 0.1% (wt/vol), the recovery coefficient for polyphenols was about 0.63, and decreased with increasing extract concentration in milk. Better polyphenol recovery was observed for grape seed extracts (0.87), with no concentration effect. Commercial extracts from whole grape, grape seed, or grape skin can be added to milk in the 0.1 to 0.3% (wt/vol) concentration range to produce cheese with potential health benefits, without a negative effect on cheese yield.
葡萄提取物可添加到牛奶中以生产富含高浓度多酚的奶酪。对来自整颗葡萄、葡萄籽和葡萄皮的四种商业提取物(两种葡萄皮提取物)进行了表征,并以0%、0.1%、0.2%和0.3%(重量/体积)的浓度添加到牛奶中。测定了葡萄提取物对牛奶凝固动力学、牛奶凝胶质地和乳清渗出的影响,并制作了模拟奶酪。整颗葡萄和葡萄籽提取物中的多酚类化合物浓度相似,约为葡萄皮提取物中含量的两倍。自由基清除活性与酚类化合物含量成正比。添加到牛奶中时,葡萄提取物会延长凝乳酶诱导的凝固时间并降低凝固速率。尽管提取物之间存在差异,但添加到牛奶中的浓度是影响凝固特性的主要因素。随着葡萄提取物浓度的增加,牛奶凝胶的脆性增加而硬度降低。此外,牛奶凝胶的乳清渗出随着葡萄提取物浓度的增加而减少,这导致奶酪的水分含量更高。牛奶中葡萄提取物的存在略微提高了奶酪中的蛋白质回收率,但对脂肪回收率没有影响。以0.1%(重量/体积)的浓度将整颗葡萄或葡萄籽提取物添加到牛奶中时,多酚的回收率约为0.63,并且随着牛奶中提取物浓度的增加而降低。葡萄籽提取物的多酚回收率更高(0.87),且无浓度效应。来自整颗葡萄、葡萄籽或葡萄皮的商业提取物可以在0.1%至0.3%(重量/体积)的浓度范围内添加到牛奶中,以生产具有潜在健康益处的奶酪,且对奶酪产量没有负面影响。