Ingredient selection criteria for probiotic microorganisms in functional dairy foods

The selection of potentially probiotic microorganisms for use in functional dairy foods is reviewed. Two groups of selection criteria are distinguished encompassing technological and medico-scientific properties. The former ensure provision of viable cultures of the desired cell density that are robust to the intended product application, while the latter ensure that the culture provided possesses activity in terms of some specified nutritional/health benefit at a specified site in the gastrointestinal tract. It is concluded that an understanding of the scientific principles and mechanisms involved in probiotic activities in the human host is continuing to emerge. Further advances will require a concerted collaborative effort between medical, pharmacological, nutritional, microbiological and technological experts. These advances will improve the basis upon which potentially probiotic microorganisms are selected and delivered by functional foods in the diet for specified human nutritional/health benefits .     

益生菌制剂及其发酵性乳制品

综述了益生菌的概念和益生菌菌株的选择标准、国外益生菌产品的发展状况、益生菌作为新型酸奶发酵剂的使用情况，以及益生酸奶的生产与消费情况。     

益生菌制剂及其发酵性乳制品

益生菌具有特殊的营养和生理功能作用,由于酸奶是益生菌的良好载体,因此益生酸奶的出现成为市场的新宠.本文综述了益生菌的概念和益生菌菌株的选择标准,益生菌作为新型酸奶发酵剂的使用情况,以及益生酸奶的生产与消费情况.     

Milk intolerance and microbe-containing dairy foods

The relationship between primary lactase deficiency, the amount of lactose in the diet, and symptoms of intolerance continues to be debated. Primary adult lactase deficiency is common with a worldwide occurrence of near 70%. Lactase-deficient individuals malabsorb lactose but may or may not show intolerance symptoms. The development of symptoms appears to depend on the dose of lactose ingested, whether it is accompanied by a meal or other food, rate of gastric emptying, and small intestine transit time. Lactose loads of 15 g or greater produce symptoms in the majority of lactase-deficient persons. However, when lactose loads of up to 12 g are fed, symptoms can be minimal or absent. Tolerance to yogurt, acidophilus milk, and other microbe-containing dairy foods has been suggested and is thought to be due to either a low lactose content or in vivo autodigestion by microbial beta-galactosidase. Up to 20 g of lactose in yogurt is tolerated well by lactase-deficient persons. Associated with the consumption of yogurt is a three- to fourfold reduction in lactose malabsorption as compared with similar lactose consumption in milk. Improved lactose digestion appears due to autodigestion by microbial beta-galactosidase. This enzyme may be released from yogurt culture by gastric or bile acid digestion. Feeding yogurt that was pasteurized following fermentation, with only trace amounts of microbial beta-galactosidase activity, results in a threefold increase in lactose malabsorption as compared with feeding yogurt with a viable culture. However, pasteurized yogurt also is tolerated well by lactase-deficient persons, suggesting that tolerance of up to 20 g of lactose in yogurt may be independent of lactose malabsorption. The enhanced lactose absorption and tolerance observed with yogurt feeding are not apparent when unfermented acidophilus milk or cultured milk are fed.     

Bacterial survival and adhesion for formulating new oral probiotic foods

Abstract

Probiotics are defined as live microorganisms, which, when administered in adequate amounts, confer health benefits to the host. Traditionally, probiotic food research has heavily focused on the genera Bifidobacteria and Lactobacilli, along with their benefits for gut health. Recently with the identification of new probiotic strains specifically intended for oral health applications, the development of probiotic foods for oral health benefits has garnered interest, with a renewed focus on identifying new food formats for delivering probiotics. The development of novel oral probiotic foods is highly complex, as the composition of a food matrix dictates: (1) bacterial viability during production and shelf life and (2) how bacteria partition with components within a food matrix and subsequently adhere to oral cavity surfaces. At present, virtually no information is available on oral probiotic strains such as Streptococcus salivarius; specifically, how orally-derived strains survive under different food parameters. Furthermore, limited information exists on the partition behavior of probiotics with food components, governed by physico-chemical interactions and adhesion phenomena. This review aspires to examine this framework by providing a foundation with existing literature related to the common probiotic genera, in order to inform and drive future attempts of designing new oral probiotic food formats.     

新型益生菌发酵乳制品的研究与开发

发酵乳营养丰富、风味独特,市场发展迅速,是益生菌在食品领域的重要产品应用形式。与嗜热链球菌、德氏乳杆菌保加利亚亚种等发酵菌株相比,益生菌在主发酵过程中参与度较低,但通过协同发酵对发酵乳的质构、风味、后酸化程度等产生一定作用,影响发酵乳品质。本文综述了益生菌对发酵乳质构、风味品质、后酸化进程的影响;分析了益生菌利用代谢及产 EPS 维持发酵乳的质构,通过产生风味化合物改善发酵乳的风味品质,以及通过影响商业发酵剂的生长而影响发酵乳后酸化进程的相关机理;总结提出了提高益生菌在发酵乳中稳定性的相关技术,以期为功能性发酵乳的研发和品质提升提供参考。

     

Screening of dairy yeast strains for probiotic applications

To evaluate the potential of yeasts of dairy origin as probiotics, we tested 8 species including Candida humilis, Debaryomyces hansenii, Debaryomyces occidentalis, Kluyveromyces lactis, Kluyveromyces lodderae, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Yarrowia lipolytica, isolated from commercial blue cheese and kefir. Strains were randomly selected from each species and tested for their ability to adhere to human enterocyte-like Caco-2 cells in culture. Among the 8 species, K. lactis showed higher adhesive ability than K. marxianus, K. lodderae, and D. hansenii. The other 4 species were poorly adhesive. All species other than K. marxianus and C. humilis were resistant to acidic conditions. In the presence of bile acid, growth inhibition was undetectable when incubation was carried out at 27 degrees C; however, it was evident for C. humilis and a strain of D. occidentalis when incubated at 37 degrees C. Moreover, the influence of proteinase treatment of living cells of K. lactis and K. lodderae on their adhesion to Caco-2 cells was evaluated. Although a slight reduction was recognized when K. lactis was treated with proteinase K, the influence of intestinal protease treatments of pepsin followed by trypsin was negligible. These results indicated that a proteinaceous factor was unlikely to be involved in adhesion of K. lactis and K. lodderae to Caco-2 cells. No stimulation of IL-8 synthesis by Caco-2 cells was recognized in the presence of K. lactis. In conclusion, K. lactis was the most attractive to continue study for use as probiotic microorganisms.     

Challenges in the addition of probiotic cultures to foods

Probiotic cultures are increasingly being added to foods in order to develop products with health-promoting properties. Although the literature is abundant on the beneficial effects of bifidobacteria and Lactobacillus acidophilus on health, little information is available on the challenges industry faces in adding these probiotic cultures to food products. The aim of this article is to examine seven issues that should be addressed when developing functional foods: 1) type or form of probiotic that should be used; 2) addition level required to have a beneficial effect; 3) toxicity; 4) effect of the processing steps on viability; 5) determination, in the product, of the cell populations added; 6) stability during storage; 7) changes in sensory properties of the foods.     

保持益生菌食品中益生菌活性的技术方法

益生菌食品是功能性食品中发展极快的一个领域。益生菌要对人体产生益生作用,必须在被食用时达到一定的活细胞数,并能在胃肠道中保持活性。如何保持益生菌食品中益生菌的活性,是食品工业面临的难题和研究热点。本文综述了目前国际上保持益生菌食品中益生菌活性的各种技术方法及研究思路,并对今后的研究方向进行了展望。     

Non-dairy probiotic food products: An emerging group of functional foods

ABSTRACT

The functional food sector has shown tremendous growth in recent years with the application of probiotic bacteria as “food additives”. The utilization of probiotic bacteria in food presents many challenges related to their growth, survival, viability, stability and functionality in food processing, storage and consumption as well as changes of sensory characteristics of probiotic foods. Although dairy foods are currently the most common food carrier to deliver probiotics, an increasing number of non-dairy food matrices exhibit potential for delivery of probiotics. This review provides more recent insight into the emergence of non-dairy probiotics products, the interactions between probiotics and different food matrices and the challenges in developing such products. Some of the technical issues are also reviewed and discussed. These issues include the efficacy of probiotic bacteria in non-chilled, low pH or high water activity foods; the potential loss of bacterial viability, additionally unwanted fermentation and changes of the sensory characteristics of food products which may result in poor microbiological quality and low acceptability to consumers.     

Nutritional and healthful aspects of cultured and culture-containing dairy foods

Nutritional and therapeutic qualities of fermented dairy products are reviewed. Partial hydrolysis of milk constituents (proteins, fats, and lactose) in yogurt, cheese, and other cultured dary foods appears to contribute to their increased digestibility. Lactase and other constituent enzymes of various culturing organisms should contribute to assimilation of lactose by lactose intolerant individuals. Several lactic cultures synthesize certain B-vitamins in fermented dairy products. In contrast, directly acidified dairy products do not exhibit such enhancement in B-vitamins. The hypocholestremic effect of milk is enhanced by fermentation or inclusion of lactic cultures. Lactobacillus acidophilus, Lactobacillus bulgaricus and other lactic organisms produce antimicrobial agents and natural antibiotics. However, production of natural antibacterial substances by different strains of the same species vary widely. These metabolites in cultured dairy products may be responsible for increased shelf life of the foods by inhibiting a wide spectrum of food spoilage organisms. Also, consumption of cultured products containing such natural antibacterial substances may provide the consumer with protection against disease organisms. Unfermented milk containing a specific culture or strain may be consumed to invest organisms for projected beneficial effects.     

Invited review: Sensory analysis of dairy foods

Sensory quality is the ultimate measure of product quality and success. Sensory analysis comprises a variety of powerful and sensitive tools to measure human responses to foods and other products. Selection of the appropriate test, test conditions, and data analysis result in reproducible, powerful, and relevant results. Appropriate application of these tests enables specific product and consumer insights and interpretation of volatile compound analyses to flavor perception. Trained-panel results differ from dairy judging and grading and one objective of this review is to clearly address and demonstrate the differences. Information on available sensory tests, when and how to use them, and the powerful results that can be obtained is presented.     

Packaging related problems with sacks of dairy powder

This paper deals with two packaging related problems occasionally encountered in the handling and storage of 25 kg sacks of dairy powder. One is caused by the production of low bulk density powder and the other is caused by excessive air entrapment in the sack. To gain a better insight into the problem, dairy powder manufacturers were visited and consultations were made with bagging machine manufacturers. The production of low bulk density powder is predominantly due to a low particle density, and the major contributory factors are total solids content, composition, state of protein denaturation of the feedstock and drier characteristics. Factors that affect excessive air entrapment in a sack are transport and storage of powder prior to bagging, powder properties and entrapment of headspace air. Possibilities for side-stepping the problem include the use of perforated liners or the development of semipermeable liners that are more permeable to air than conventional liners.