Effect of fat replacers on kefir quality

The purpose of the study was to determine the effects of fat replacers on the quality of non‐fat kefir. Skim milk fortified with Dairy Lo^® (DL) and inulin (INU) was fermented with kefir grains to manufacture kefir. The results of compositional, microbiological, rheological and sensorial analyses were compared with whole kefir (WK) and non‐fat kefir (NFK) controls. Results for dry matter, pH and lactic acid ranged between 82.4 and 109.1 g kg^?1, 4.26 and 4.40, and 7.0 and 9.2 g L^?1, respectively. Acetaldehyde and ethanol contents of samples were between 2.89 and 7.28 mg L^?1, and 151.46 and 323.89 mg L^?1, respectively. In all samples, Lactobacillus spp., Streptococcus spp. and yeast counts were between 9.1 and 9.9, 9.3 and 9.9, and 5.2 and 5.6 log cfu mL^?1, respectively. Kefir samples had non‐Newtonian behaviour and pseudoplastic fluid with thixotropy. At the first day, DL had the highest apparent viscosity (3.119 Pa s) while NFK had the lowest value (1.830 Pa s). In the sensory evaluation, odour and taste scores of samples were not different. Dairy Lo^® and inulin could be used without any adverse effect for the production of non‐fat kefir. Copyright © 2009 Society of Chemical Industry     

The effect of inulin as a fat replacer on the quality of set-type low-fat yogurt manufacture

The influence of different levels of inulin on the quality of fat-free yogurt production was investigated. Inulin was added to milk containing 0.1% of milk fat to give inulin levels of 1, 2 and 3%. The experimental yogurts were compared with control yogurt produced from whole milk. The total solids content of milk was standardized to 14% by adding skim milk powder to the experimental yogurt. The chemical composition, pH, titratable acidity, whey separation, consistency, acetaldehyde and volatile fatty acidity contents were determined in the experimental yogurts after 1, 7 and 15 days. Sensory properties of the yogurts were evaluated during storage. The addition of inulin at more than 1% increased whey separation and consistency. Acetaldehyde, pH and titratable acidity were not influenced by addition of inulin. Tyrosine and volatile fatty acidity levels were negatively affected by inulin addition. With respect to the organoleptic quality of yogurt, inulin addition caused a decrease in organoleptic scores: the control yogurt had the highest score, and the lowest score was obtained in yogurt samples containing 3% of inulin. Overall, the yogurt containing 1% of inulin was similar in quality characteristics to control yogurt made with whole milk.     

Texture of nonfat yoghurt as influenced by whey protein concentrate and Gum Tragacanth as fat replacers

Seven batches of nonfat yoghurt stabilized with different concentrations of whey protein concentrate (WPC) and Gum Tragacanth (GT) were produced to study the effects of WPC and GT as fat replacers on the rheological properties of yoghurt. By increasing the WPC up to 15 g/L, storage modulus (G'), loss modulus (G") and complex dynamic viscosity (η*) values were increased and sensory impressions of texture and appearance were improved when compared with the control nonfat yoghurt. Addition of gum above 0.5 g/L led the decrease of G', G", η* and resulted in lower scores for sensory attributes than control nonfat yoghurt.     

The effect of inulin as a fat replacer on the quality of low‐fat ice cream

The influence of different levels of inulin as fat replacer on the quality of ice cream was investigated. Inulin was added at 2, 4 and 6% to replace milk fat and the experimental ice creams were compared to a control with 10% milk fat. The chemical composition, overrun, water activity, viscosity, melting rate, hardness and colour value were determined. Sensory properties of the ice cream samples were evaluated during storage. The overall acceptability of ice creams prepared with 2 and 4% substitution were similar to the control.     

The antiallergic effect of kefir Lactobacilli

This study demonstrated that oral feeding of heat-inactivated Lactobacillus (L b.) kefiranofaciens M1 from kefir grains effectively inhibited immunoglobulin (Ig) E production in response to ovalbumin (OVA) in vivo. The pattern of cytokine production by splenocyte cells revealed that the levels of cytokines produced by T helper (Th) 1 cells increased, and those of cytokines produced by Th2 cells decreased in the heat-inactivated M1 feeding group. These findings indicated that Lactobacillus kefiranofaciens M1 in the kefir played an important role in antiallergic activities. By additional analysis using flow cytometry and microarray, the mechanism of suppression of IgE production by oral feeding of the heat-inactivated M1 probably occurs because of upregulation of the expression of Cd2, Stat4, and Ifnr leading to skewing the Th1/Th2 balance toward Th1 dominance, elevation of the CD4(+)CD25(+) regulatory T (Treg) percentage, and reduction of activated CD19(+) B cells. Downregulation of complement system and components was also involved in suppression of IgE production. Practical Application: Kefir has long been considered good for health. Its health benefits include immunoregulatory effects. However, there is a lack of knowledge concerning the immunoregulatory effects induced by kefir lactic acid bacteria (LAB). Our data clearly demonstrated the antiallergic activity of kefir LAB, Lactobacillus (L b.) kefiranofaciens M1. By additional analysis using flow cytometry and microarray, the possible mechanism of suppression of IgE production by oral feeding of the heat-inactivated M1 was also elucidated. Our findings indicated that Lactobacillus kefiranofaciens M1 may have a great potential for utilization in functional food products.     

低聚异麦芽糖理化功能特性及生产方法研究进展

低聚异麦芽糖是由α-1,6-糖苷键结合的功能性低聚糖,具有优良的理化特性和显著的生理功能,广泛应用于医药、食品、保健品及饲料行业。文中综述了低聚异麦芽糖的理化特性和生理功能,并从酶催化、分离纯化环节探讨了低聚异麦芽糖的生产技术。     

分离自藏灵菇的乳酸菌的益生特性

从藏灵菇中分离纯化5株乳酸菌,初步鉴定2株为嗜酸乳杆菌,3株为乳酸乳球菌。选取其中2株菌研究其益生特性。结果表明,从藏灵菇中分离出的乳酸菌具有良好的益生特性,2株乳酸菌在pH值为4～6可生长良好;耐热范围为30～60℃;胆盐耐受性为0.1%～0.5%;发酵液对金黄色葡萄球菌、沙门氏菌、大肠杆菌等肠道病原菌有抑制作用;对抗生素有不同程度的耐药性。     

Effect of the type of fat on rheology,functional properties and sensory acceptance of spreadable cheese analogue

The objective of this work was to evaluate the effect of different types of fat (butter oil, partially hydrogenated soybean fat and soybean oil) on the functionality, rheology and sensory acceptance of spreadable cheese analogues. Analogues made with partially hydrogenated soybean fat or soybean oil in substitution to butter oil presented lower fat globule size. As a consequence, these analogues showed lower melting, lower spreadability, higher hardness and higher values for the elastic and viscous moduli than cheese made with butter oil. Despite not managing to imitate the flavour of the traditional cheese, the analogue made with partially hydrogenated soybean fat showed good sensory acceptance.     

The effect of in vitro gastrointestinal simulation on bioactivities of kefir

Kefir is a fermented milk beverage and known to have positive effects on gut microbial diversity and human health. In this study, digested and undigested kefir samples were compared for changes in their antihypertensive, antidiabetic, antioxidant and antimicrobial activities. Results showed that the amount of total phenolic substances, 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH) activity, and the angiotensin-converting enzyme inhibitor (ACE-I) activity increased from 43.76 ± 0.005 mg gallic acid equivalents (GAE)/L, 4.20 ± 0.55%, and 9.91 ± 3.90% in undigested kefir to 668.16 ± 3.332 mg GAE/L, 63.06 ± 0.64%, and 98.88 ± 0.42% in digested kefir, respectively. While the dipeptidyl peptidase IV-inhibitory (DPPIV-I) activity of undigested kefir increased by 19.11 ± 7.35% after digestion, the optical density of the ferric-reducing antioxidant power (FRAP) decreased from 1.188 ± 0.05 to 0.278 ± 0.009, and the protein amount decreased from 101.4 mg L⁻¹ to 12.42 mg L⁻¹ in digested kefir. No antimicrobial effect was observed in undigested kefir, whereas, digested kefir samples were active, but only against Escherichia coli. These results show that the gastrointestinal digestion processes of kefir generally increase the number of bioactive molecules, and the digestion process must be taken into account to determine the biological capability of foods.     

戊聚糖及其对面粉品质的影响

本文论述了戊聚糖的化学性质、在谷物中的含量、分布及其对面粉功能品质的影响.文中的实验结果表明,戊聚糖(由小麦麸皮制备)对面团的流变学性质及烘焙品质有着重要的影响.氧化胶化作用试验、粘度及组份测定结果还表明,这种影响的化学本质是戊聚糖和蛋白质通过阿魏酸桥梁产生了大分子量物质.     

Study of immune cells involved in the antitumor effect of kefir in a murine breast cancer model

Administration of kefir and a kefir cell-free fraction (KF) to mice injected with breast tumor cells produced, locally in the mammary gland, different profiles of cells secreting cytokines. Here, the immune cell populations in mammary glands affected by the cyclic consumption of kefir or KF for 2 or 7 d were evaluated using a breast tumor model. Apoptosis was also assayed as another mechanism involved in tumor growth delay. The rate development of tumor cells, IgA(+) cells, and CD4+ and CD8+ T lymphocytes was monitored in mammary gland tissues. The number of Bcl-2(+) cells in the mammary gland was compared with the apoptosis observed in the tumor. Two-day cyclical administration of both products delayed tumor growth and increased the number of IgA(+) cells in the mammary gland. Changes in the balance between CD4+ and CD8+ cells in the mammary gland were observed in mice from the group fed KF cyclically for 2 d, such that the number of CD4+ cells increased when the number of CD8+ cells remained constant. Mice that received 2-d cyclic administration of KF showed significant increases in the number of apoptotic cells and decreases in Bcl-2(+) cells in the mammary gland, compared with the tumor control group. The present study allows a better understanding of the mechanisms (immune and nonimmune) involved in the antitumor effect observed in mice administered kefir or KF. The importance of nonmicrobial components released during milk fermentation to obtain the beneficial antitumor effects is also reported.     

Modulation of the intestinal microbiota of dogs by kefir as a functional dairy product

Kefir is a traditional dairy product with multiple probiotic characteristics derived from its associated microorganisms, including more than 50 species of lactic acid bacteria and yeast. For centuries, many people have produced kefir for human consumption; its consumption and potential role as a probiotic supplement in companion animals have never been tested. The present study explored the potential application of kefir as a probiotic supplement for dogs. Kefir was orally administered to healthy adult dogs (n = 6) for 2 wk. On d 0 and 14 (before and after kefir consumption, respectively), gut microbiota was analyzed comprehensively using quantitative PCR and 16S rDNA amplicon-based community analysis using fresh fecal samples. The 16S rDNA amplicon-based community analysis showed that the relative abundance of the phylum Fusobacteria was significantly decreased after kefir consumption. Furthermore, the relative abundance of the families Prevotellaceae, Selenomonadaceae, and Sutterellaceae increased significantly, whereas that of the families Clostridiaceae, Fusobacteriaceae, and Ruminococcaceae decreased significantly. The quantitative PCR assay showed that kefir consumption significantly increased the population of lactic acid bacteria and the lactic acid bacteria:Enterobacteriaceae ratio and significantly decreased the Firmicutes:Bacteroidetes ratio. In summary, 2-wk kefir administration successfully modified the gut microbiota without causing any clinically evident adverse effects. Therefore, kefir could be further developed as a novel probiotic food supplement for dogs to improve the quality of life of dogs.     

The anti‐allergenic properties of milk kefir and soymilk kefir and their beneficial effects on the intestinal microflora

Food allergy is now recognized as a worldwide problem, and like other atopic disorders its incidence appears to be increasing. Kefir is reported to possess the ability to reduce intestinal permeation of food antigens; however, no experimental study has clearly evaluated the relationships between kefir consumption, allergen‐specific IgE response, and intestinal microflora. The aim of this study was to evaluate the effect of oral consumption of milk kefir and soymilk kefir on in vivo IgE and IgG1 production induced by ovalbumin (OVA) in mice. The effects of kefir administration on the murine intestinal microflora were also examined. Oral administration of milk kefir and soymilk kefir for 28 days significantly increased the fecal populations of bifidobacteria and lactobacilli, while it significantly decreased those of Clostridium perfringens. Milk kefir and soymilk kefir also significantly decreased the serum OVA‐specific IgE and IgG1 levels for both groups, but not those of the IgG2a analogues. Consumption of milk kefir and soymilk kefir suppressed the IgE and IgG1 responses and altered the intestinal microflora in our supplemented group, suggesting that milk kefir and soymilk kefir may be considered among the more promising food components in terms of preventing food allergy and enhancement of mucosal resistance to gastrointestinal pathogen infection. Copyright © 2006 Society of Chemical Industry     

Effect of modified starch from sweet potato as a fat replacer on the quality of reduced fat ice creams

In the present study, application of different levels (0, 1 and 2%) of citric acid treated sweet potato starch as a fat replacer (FR) in a high (11% fat), medium (6% fat) and low-fat (1%) ice creams were investigated. Results indicated that hardness value tends to improve with the addition of 1% FR in all reduced fat ice creams. During 60 days of storage, a decreasing trend was noticed in overrun, acidity and hardness values of ice cream samples. Overall score of sensory conveyed that the reduced fat ice creams with 1% FR (medium fat ice cream and low fat ice cream) were found to be very acceptable by sensory panels with a similar physicochemical characteristics and acceptance as high-fat ice cream (control) at the end of storage period. Citric acid treated sweet potato starch proved to be a promising alternative as a fat replacer in the ice cream production.     

Rheological properties,stability and sensory evaluation of low-cholesterol mayonnaises prepared using egg yolk granules as emulsifying agent

No important practical applications have been developed for egg yolk granules until now. However, as they have low cholesterol content and maintain good emulsifying properties, granules could be employed as a potential ingredient in the food industry. In this work, granules obtained in the laboratory by a simple procedure were used as emulsifying agent in mayonnaise preparation. The aim was to develop a low-cholesterol mayonnaise with properties similar to those of typical mayonnaise. For this purpose, three low-cholesterol formulations prepared in the laboratory were compared with a mayonnaise prepared using yolk and also with a commercial mayonnaise. The rheological characteristics of mayonnaises were evaluated, as well as their microstructure and sensorial properties. In addition, colour and particle size measurements at different times of storage were carried out to assess stability. According to results, the use of granules allows the preparation of a low-cholesterol mayonnaise which shows similar characteristics to those of a typical mayonnaise.     

Effect of modified cassava starch as a fat replacer on the texture and quality characteristics of muffins

The aim of this study was to evaluate the effects of modified cassava starch as a partial fat replacer on the quality characteristics of muffins. Cross-linked cassava starch (CCS) was used to replace fat at 8, 12 and 16% substitution levels, based on the total weight of the wheat flour. The thermal properties of the CCS and wheat flour were assessed, and the pasting and farinographic properties of the wheat flour-CCS mixtures were also evaluated. The addition of CCS had an adverse effect on the dough stability and development time, which decreased as the amount of CCS increased in the mixture. The gelatinization and retrogradation entalphies of the CCS were higher than those of the wheat flour. The final and setback viscosities of the wheat flour were higher than those of the wheat flour-CCS mixtures. Furthermore, the quality and textural characteristics of the muffins were determined. There were no significant differences in the weight loss, specific volume, crumb moisture content or color parameters of the muffins. The muffins containing CCS at fat replacement levels of 8% (T8) had the textural properties that were closest to those of the muffins without the CCS (control sample). Thus, this sample was chosen to evaluate the storage behavior over 7 days along with the control muffins. The T8 samples had a higher crumb firmness during the storage. There were no significant differences in the overall acceptability of the T8 and control muffins on days 2 and 4 of the storage. So, the T8 muffins had good acceptability by consumers despite having a higher firmness during the storage.     

A soluble fibre gel produced from rice bran and barley flour as a fat replacer in Asian foods

A hydrocolloidal fibre composite made from rice bran and barley flour, called Ricetrim, was found to have similar rheological properties to coconut cream. Coconut cream displayed a very narrow region of linear viscoelastic behaviour, both above and below strain values of 0.1%, the oscillatory shear modulus dropped sharply with increasing strain, indicating non‐linear viscoelastic behaviour. This region of linear viscoelastic behaviour extended to strains of 10%. When Ricetrim was substituted for coconut cream in Thai foods, it was found to produce acceptable products, but with lower saturated fat contents. Cookies, pumpkin pudding, layer cake, dip for pot crust, taro custard and sauté chicken curry were produced with fat contents reduced by 47.8, 94.3, 59.8, 75.3, 61.3 and 60.6%, respectively. Some differences in flavour and texture were observed at the higher levels of substitution, but these differences appeared to present only small changes in the overall score of general acceptability, or suitability, of the fibre gel foods. Scanning electron micrographs of the pumpkin pudding revealed only small changes in their surfaces with Ricetrim addition, even at higher levels of substitution.