The effects of probiotics in lactose intolerance: A systematic review

Over 60 percent of the human population has a reduced ability to digest lactose due to low levels of lactase enzyme activity. Probiotics are live bacteria or yeast that supplements the gastrointestinal flora. Studies have shown that probiotics exhibit various health beneficial properties such as improvement of intestinal health, enhancement of the immune responses, and reduction of serum cholesterol. Accumulating evidence has shown that probiotic bacteria in fermented and unfermented milk products can be used to alleviate the clinical symptoms of lactose intolerance (LI). In this systematic review, the effectiveness of probiotics in the treatment of LI was evaluated using 15 randomized double-blind studies. Eight probiotic strains with the greatest number of proven benefits were studied. Results showed varying degrees of efficacy but an overall positive relationship between probiotics and lactose intolerance.     

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.     

Lactase Activity of Cultured and Acidified Dairy Products

A method was standardized for determining lactase activity in cultured and acidified dairy products such as cottage cheese, sour cream, and yogurt. Cottage cheese and sour cream prepared by both the cultured and acidified processes and yogurt prepared by the direct acidification process did not possess lactase activity. However, cultured yogurt possessed considerable enzyme activity mainly due to lactase as an endoenzyme in the yogurt culture (Lactobacillus bulgaricus and Streptococcus thermophilus). Enzyme in yogurt increased with time of incubation, reaching a maximum of 8 orthonitrophenol β-d-galactopyranoside units per gram of yogurt in 4 h. S. thermophilus contained approximately three times more lactase than did L. bulgaricus. Also, an in vitro digestion process appeared to enhance the release of lactase from the composite yogurt culture. It was felt that cultured yogurt would be beneficial to individuals suffering from lactose intolerance not only because of reduced lactose but also because of lactase.     

Fermented Milks and Milk Products as Functional Foods—A Review

Fermented foods and beverages possess various nutritional and therapeutic properties. Lactic acid bacteria (LAB) play a major role in determining the positive health effects of fermented milks and related products. The L. acidophilus and Bifidobacteria spp are known for their use in probiotic dairy foods. Cultured products sold with any claim of health benefits should meet the criteria of suggested minimum number of more than 10⁶ cfu/g at the time of consumption. Yoghurt is redefined as a probiotic carrier food. Several food powders like yoghurt powder and curd (dahi) powder are manufactured taking into consideration the number of organisms surviving in the product after drying. Such foods, beverages and powders are highly acceptable to consumers because of their flavor and aroma and high nutritive value. Antitumor activity is associated with the cell wall of starter bacteria and so the activity remains even after drying. Other health benefits of fermented milks include prevention of gastrointestinal infections, reduction of serum cholesterol levels and antimutagenic activity. The fermented products are recommended for consumption by lactose intolerant individuals and patients suffering from atherosclerosis. The formulation of fermented dietetic preparations and special products is an expanding research area. The health benefits, the technology of production of fermented milks and the kinetics of lactic acid fermentation in dairy products are reviewed here.     

Lactose hydrolysis and other conversions in dairy products: Technological aspects

Most of the world populations lose part of their lactase activity in the small intestine after the childhood. Many traditional dairy products like ripened cheeses are naturally lactose-free. New technologies to produce lactose-free fresh dairy products have been developed during the last decades to satisfy the needs of the people suffering from lactose intolerance. This article provides a review of this new technological development work in the dairy industry.     

Probiotic potentials of cereal-based beverages

Probiotics offer remarkable potential for the prevention and management of various infective and noninfective disorders. They are reported to play key roles in the suppression of gastrointestinal infections, antimicrobial activity, improvement in lactose metabolism, reduction in serum cholesterol, immune system stimulation, antimutagenic properties, anticarcinogenic properties, anti-diarrheal properties, and improvement in inflammatory bowel disease. Although probiotic foods are classically confined to beverages and cheese, containing live organisms of the lactic acid bacteria family, such health-promoting foods are traditionally dairy-based, comprising milk and its fermented products. However, recent research focuses on the probiotic potentials of fermented cereal-based beverages which are especially consumed in developing countries characterized by low nutritional security and high incidence of gut pathogen infections. Moreover, lactose intolerance and cholesterol content associated with dairy products, coupled with the vegetarian tendencies of diverse populations in the third world, tend to enforce the recent recourse to nondairy beverages. Probiotic microorganisms are mostly of human or animal origin; however, strains recognized as probiotics are also found in nondairy fermented substrates. This review examines the potentials of some traditional cereal-based beverages to serve as probiotic foods, their microbial and functional properties, as well as their process optimization and storage for enhanced utilization.     

生物技术在乳糖不耐受防治中的应用

原发性乳糖酶缺乏和乳糖不耐受（吸收不良）是全球性的健康问题。从基因工程技术生产乳糖酶、利用生物反应器生产低乳糖奶、基因治疗等3个方面介绍了生物技术在乳糖不耐受（吸收不良）防治中的应用，并提出口服经改造的益生菌制剂，从根本上解决乳糖酶缺乏的新思路。     

乳糖在人体内的营养特性

乳糖是乳中惟一的碳水化合物,最易被人体吸收,被人体吸收后可变成多肽、氨基酸和脂肪酸,从而提高乳蛋白和乳脂的利用率。由于乳糖酶的缺乏,许多患有乳糖不耐受的人不能食用乳制品。从乳糖的含量、乳糖的消化代谢过程和乳糖不耐受的分类以及乳糖的营养功能进行阐述。     

Development and Evaluation of Whole-Cell Yeast Lactase for Use in Dairy Processing

A low-cost industrial grade lactase was developed for one-time use in dairy products. The preparation contained the entire biomass of a selected hyperproducing strain of the yeast Kluyveromyces fragilis. Intracellular lactase was made freely accessible to its substrate by permeabilization of the cell membrane with food compatible reagents. In 0.1M phosphate plus 0.4% methyl paraben, permeabilization was complete in 0.5–1 hr at 50°C, with 90% activity recovery from 180 g/L of cells. Whole-cell lactase contained no viable cells and was free of proteolytic activity. Its pH optimum of 5.6–6.0 proved suitable for lactose hydrolysis concurrent with cottage cheese fermentation. Hydrolyzed whey was used in ice cream and bakers' yeast production.     

酶法制备低乳糖牛奶的研究

该文主要研究探讨酶法生产低乳糖牛奶产品的工艺条件及配方。试验研究结果表明,乳糖酶加量为1500NLU/L、酶解时间3·0h,乳糖的水解率可达60%以上,可满足部分患有乳糖不耐症人群的需要,增加了牛奶制品的花色品种。     

Probiotic fermentation of plant based products: possibilities and opportunities

Functional foods are claimed to have several health-specific advantages. In addition to their basic nutritive value, they contain a proper balance of ingredients which help in the prevention and treatment of illnesses and diseases. Within this category, products containing lactic acid bacteria or probiotics are increasingly gaining importance. The recognition of the beneficial effects of dairy products containing probiotics has been well established. The allergy to dairy products, lactose intolerance, and cholesterol content are the major drawbacks related to the use of fermented dairy products for a large percentage of consumers. Modern consumers are increasingly interested in their personal health, and expect the food that they eat to be healthy or even capable of preventing illness. Because of this, probiotic food products made out of fermentation of cereals and fruits and vegetables is receiving attention from the scientific world as well as consumers and constitutes the major part of this review. The use of mathematical models for the probiotic fermentation will help in reducing the time and effort involved in the optimization of the probiotic fermentation process. We have tried to summarize the developments in the use of mathematical models for probiotic fermentation. Future technological prospects exist in innovations which represent solutions for the stability and viability problems of probiotics in new food environments. Current research on novel probiotic formulations and microencapsulation technologies exploiting biological carrier and barrier materials has also been discussed.     

Cloning,expression, and bioinformatics analysis and characterization of a β-galactosidase from Bacillus coagulans T242

The activities of β-galactosidases from bacteria and molds are affected by temperature, pH, and other factors in the processing of dairy products, limiting their application, so it is necessary to find alternative lactases. In this study, the β-galactosidase gene from Bacillus coagulans T242 was cloned, co-expressed with a molecular chaperone in Escherichia coli BL21, and subjected to bioinformatic and kinetic analyses and lactase characterization. The results show that the enzyme is a novel thermostable neutral lactase with optimum hydrolytic activity at pH 6.8 and 50°C. The thermal stability and increased lactose hydrolysis activity of β-galactosidase in the presence of Ca²⁺ indicated its potential application in the dairy industry.     

Functional cultures and health benefits

A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and L. casei. These benefits include antimutagenic effects, anticarcinogenic properties, improvement in lactose metabolism, reduction in serum cholesterol, and immune system stimulation. Because of the potential health benefits, these organisms are increasingly being incorporated into dairy foods, particularly yoghurt. In addition to yoghurt, fermented functional foods with health benefits based on bioactive peptides released by probiotic organisms, including Evolus^® and Calpis^®, have been introduced in the market. To maximize effectiveness of bifidus products, prebiotics are used in probiotic foods. Synbiotics are products that contain both prebiotics and probiotics.     

Probiotics: An emerging food supplement with health benefits

Probiotics are among the important functional foods. They comprise approximately 65% of the world functional food market. Probiotic products are foods, which improve intestinal microflora and support good health of the consumer. The live bacteria present in the probiotic products are lactic acid bacteria, including Lactobacilli, Bifidobacteria and Enterococci. Apart from health claims and maintenance of intestinal microflora, they protect against infections, alleviate lactose intolerance, reduce blood cholesterol levels and also stimulate the immune system. The interactive research between physiology, microbiology, food technology and molecular biology followed by clinical trials may produce a multi-functional probiotic strain for human consumption.     

Production of low-dosage lactose milk using lactase immobilised in hydrogel

A hydrogel based on chitosan was employed for the immobilisation of lactase with the aim of hydrolysing lactose and producing low-dosage lactose milk. The degree of swelling of the hydrogel was affected by the type of aqueous solution, pH and temperature. The lactase immobilisation capacities at pH 4.0 and pH 7.0 were 257.12 ± 3.18 and 157.87 ± 1.96 mg enzyme per g dried hydrogel, respectively, after 1440 min at room temperature. The activity of immobilised lactase ranged from 97.91 to 56.04 and 97.91 to 71.80% from the first to the tenth cycle of hydrolysis of standard lactose and lactose contained in UHT milk, respectively. Immobilised lactase in hydrogel could be applied for the production of low-dosage lactose milk for at least ten successive hydrolysis cycles. Moreover, hydrogels containing immobilised lactase could also be useful for the enzyme release in individuals with lactose intolerance.     

高产β-半乳糖苷酶植物乳杆菌的筛选及其酶学性质研究

β-半乳糖苷酶不仅能通过分解乳制品中乳糖解决乳糖不耐症问题,同时能通过转糖苷作用合成具有益生功能的低聚半乳糖。从8株植物乳杆菌中筛选出高产β-半乳糖苷酶菌株K2,比活力高达6620 U/g,并对β-半乳糖苷酶酶学性质进行研究。结果表明:β-半乳糖苷酶最适和最稳定的pH值为6.5,最适温度为60℃,而在40℃稳定性最强。Mg2+对β-半乳糖苷酶活力有明显促进作用,而Cu2+有强烈抑制作用,通过推导求得米氏常数Km,oNPG=1.15 mmol/L,最大反应速率Vmax,oNP=6.34μmol/(min.mg)。研究结果为具有解决乳糖不耐受症的植物乳杆菌微生态制剂的开发奠定了基础。     

抗乳糖不耐受添加剂的研究

对产乳糖酶的三株乳酸菌进行协同发酵制成抗乳糖不耐受添加剂,冻干的乳糖酶在4℃贮存三个月活性基本不变,确立抗乳糖不耐受添加剂乳酸菌添加浓度为107/L。     

低乳糖奶的应用与发展

牛奶是营养丰富、容易消化吸收的天然食品。但是由于乳 糖不耐症的存在,使较多消费者饮用牛奶后会出现消化不 良、腹胀等现象。而低乳糖牛奶的开发满足了乳糖不耐症 患者的乳品消费需求,又改善了其他一些乳制品的加工工 艺条件和产品品质,促进了我国乳制品工业的发展。     

The effect of yoghurt on the growth,lactose-utilizing gut organisms and β-glucuronidase activity of caecal contents of a lactose-fed,lactase-deficient animal

The chicken, which has no endogenous lactase, was assessed as a possible model for studies on lactose intolerance. The ability of yoghurt to reverse changes induced by lactose was examined. In the caecum lactose had little effect on the viable counts of three groups of organisms which utilize lactose and no effect on the water content. It suppressed body weight, induced gas formation in the caecum and slightly lowered caecum pH. None of these effects was reversed by yoghurt.The β-glucuronidase activity of the caecal contents was slightly reduced by lactose and markedly reduced in chickens receiving lactose and yoghurt. The additional effect of yoghurt also occurred with yoghurt which had been heated to kill the bacteria and inactivate the lactase. The suppression of β-glucuronidase activity was also achieved by supplements of yoghurt alone.     

益生乳酸菌在乳制品中的应用研究进展

益生乳酸菌是一类能利用碳水化合物发酵产生大量乳酸,且对宿主有益的微生物。乳制品在人类膳食结构中占有十分重要的地位,随着消费者对乳品品质和健康要求的提升,具有各种健康功能的益生乳酸菌在乳品中的应用及相关加工技术和功能产品的研发日益受到关注。通过添加益生乳酸菌等活性因子获得功能性乳制品,是增强乳品健康功效的有效方法。本文综述了近年来有关益生乳酸菌在发酵乳、干酪、乳饮料、冰淇淋和奶粉等乳制品中的应用研究现状,重点介绍了益生乳酸菌发挥功能的主要代谢产物酶类和胞外多糖的应用研究,包括在不同乳制品中益生乳酸菌及其产物发挥的作用,常用的益生乳酸菌菌株种类,生产加工过程中存在的主要问题及解决方法,为益生乳酸菌在乳制品中的应用开发提供参考。