大豆油体替代牛乳脂肪对牛乳稳定性及其酸乳品质的影响

本研究首先从大豆种籽中提取大豆油体,然后将大豆油体替代牛乳中的脂肪,探讨大豆油体替代牛乳脂肪乳在不同环境下的稳定性,最后将大豆油体替代牛乳脂肪乳进行酸乳加工,以无水奶油替代牛乳脂肪乳及牛乳进行对照,考察大豆油体替代牛乳脂肪乳对牛乳稳定性及酸乳品质的影响。结果表明,大豆油体替代牛乳脂肪乳、无水奶油替代牛乳脂肪乳及牛乳在pH 2.0和4.0时,粒径较大。在pH 2.0~10.0,大豆油体替代牛乳脂肪乳的粒径显著高于无水奶油替代牛乳脂肪乳及牛乳的粒径(P<0.05)。除200 mmol/L外,在NaCl浓度0~500 mmol/L条件下,大豆油体替代牛乳脂肪乳的平均粒径显著高于无水奶油替代牛乳脂肪乳及牛乳的粒径(P<0.05),但是3种乳液油滴均没有明显的聚集,表现较稳定。在不同热处理温度条件下,大豆油体替代牛乳脂肪乳、无水奶油替代牛乳脂肪乳及牛乳都具有较高的热稳定性。大豆油体替代牛乳脂肪乳经过6 h发酵后其pH值能达到酸乳的理想pH值4.5左右,而且用时较无水奶油替代牛乳脂肪乳及牛乳短。大豆油体替代牛奶脂肪乳发酵形成的酸乳黏度显著高于无水奶油替代牛乳脂肪乳及牛乳发酵的酸乳的黏度(P<0.05),而且酸乳的感官和质地均较好。本研究可为大豆油体替代牛乳脂肪进行乳制品加工提供参考。

不同氧化度的魔芋葡甘露聚糖对凝固型酸奶品质的影响

“健康低脂”的食品理念近来广受大众欢迎。为改善低脂凝固型酸奶的凝胶强度低等问题,向酸奶中添加氧化魔芋葡甘露聚糖(Oxidized konjac glucomannan,OKGM)作为脂肪替代物,通过对酸奶理化性质、质构、流变学特性和微观结构等指标的分析,探究不同氧化度OKGM对酸奶品质的影响。结果表明,含高氧化度的OKGM(OK-60、OK-90、OK-120)的酸奶与未添加OKGM的酸奶相比,硬度从375.90 g提高至436.67 g,持水力从28.03%提高至31.89%,同时,能够提高流变学特性中的表观黏度和粘弹性。扫描电镜和激光共聚焦结果显示,高氧化度的OKGM缩小了酸奶凝胶结构间的孔隙,提高了酪蛋白胶束间的聚集,使其平均粒径从88.27 nm增加到125.33 nm。然而,天然的魔芋葡甘露聚糖(Konjac glucomannan,KGM)和低氧化度的OKGM(OK-30)则会降低酸奶的质构、表观黏度和粘弹性,破坏酸奶的凝胶结构,导致其稳定性下降。感官评价结果显示,高氧化度的OKGM使酸奶更有光泽,体系更加均匀,且在滋味上更具优势,这也为健康低脂酸奶的开发奠定了理论基础。

桑葚魔芋酸奶的研制

以牛奶、桑葚汁、魔芋胶和白砂糖等为原料,研制出一款风味营养兼具的桑葚魔芋酸奶。以感官评分作为评价指标,通过单因素试验和正交试验进行桑葚魔芋酸奶的配方优化。结果表明,最佳配方为每份桑葚魔芋酸奶中白砂糖添加量6.0%,魔芋胶添加量0.2%,发酵剂添加量4.0%,桑葚汁添加量12.0%。经此工艺制作而成的酸奶色泽均匀、呈浅粉色,组织细腻、无裂纹、无乳清析出,口感酸甜适中,有浓郁的发酵风味和桑果香味。品质评价结果显示,桑葚魔芋酸奶的持水力为83%,总酸度为97.0°T,可溶性固形物含量为14.0%,均符合国家标准,是一款兼具风味和营养的功能性酸奶产品。

小麦低聚肽制备凝固型酸奶及其发酵特性的研究

选取3种酶(胃蛋白酶、碱性蛋白酶和风味蛋白酶)对谷朊粉进行水解,将不同酶解时间得到的小麦低聚肽加入酸奶中,代替部分牛奶蛋白(3%),以酸奶的pH值、滴定酸度为指标进行感官评价及质构分析,筛选出促酸奶发酵能力较好的酶解物,然后将小麦低聚肽按分子质量进行超滤膜分离,并评价和比较不同肽段的促酸奶发酵能力。结果表明,用碱性蛋白酶水解小麦面筋蛋白24 h的小麦低聚肽促酸奶发酵能力最佳,其中分子质量为1.5~3.5 kU的肽段极大地缩短酸奶的发酵周期,改善了酸奶的感官结构特性。

Probiotics Bacteria from Egyptian Infants cause Cholesterol Removal in Media and Survive in Yoghurt

One of the most significant groups of probiotic organisms are the lactic acid bacteria, commonly used in fermented dairy products. In this study, cultures were isolated from two infants. After screening for the classic properties of probiotic organisms, four promising isolates were identified as two strains of Lactobacillus acidophilus (P106, P110), strain of Lactobacillus plantarum (P164) and Lactobacillus. pentosus (P191)which were tested for capability to remove cholesterol and to deconjugate sodium taurocholate from the culture medium. Results showed that a considerable variation existed among cultures in their growth viability in the presence of bile salt, deconjugation of sodium tauro-cholate and assimilation of cholesterol from the medium. All tested strains removed less cholesterol from the broth (ranged from 4.02-24.32%) compared to those grown in broth supplemented with 0.2% bile salts (from 29.02 to 45.3). Lactobacillus acidophilus P106 appeared to be more active in bile salt hydrolase compared to the other strains, and therefore, is regarded as a suitable candidate probiotic and adjunct culture.These strains were employed to make yo-ghurt and, in order to achieve a short production time;a two-stage fermentation procedure was used with Streptococ-cus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus providing the rapid acidification. Storage trials at 4o C showed that the viability of the probiotic cultures was retained over 15 days.

Chemical, Nutritional, Rheological, and Organoleptical Characterizations of Stirred Pumpkin-Yoghurt

Pumpkin contains considerable amounts of bioactive compounds which hardly valorized in dairy products. This study aims to investigate the chemical, nutritional, rheological, and organoleptical properties of prepared stirred pumpkin-yoghurt. Stirred yoghurt with three different pumpkin varieties pulp [American (AP), Domestic (DP), and Indian (IP) pumpkin] at 15% was prepared and stored at 5°C ± 1°C up to 14 d. The chemical properties of yoghurts include protein, fat, crude fiber, and available carbohydrates were significantly affected by adding pumpkin without remarkable change in caloric value. Addition of pumpkin pulps decreased the pH and increased the acidity of stirred pumpkin-yoghurt significantly (P -1 in all stirred yoghurts after 1 d. After that, it was increased without notable effect of adding pumpkin pulps, and with slight simulation in LAB, growth was noticed in DP and IP yoghurts. Total phenolic compounds (TPC), total flavonoid (TF), total flavonols (TFL), carotenoids contents, and antioxidant capacity of pumpkin-yoghurts were significantly increased. Fortifying yoghurt with pumpkin pulp was associated with a statistically significant effect on sensory parameters such as flavor, color, and overall acceptability. Scores of AP yoghurt showed the highest score which significantly differed from CY. It is obviously showed that panelists were favored the prepared stirred pumpkin-yoghurt. Thus, it is recommended that adding pumpkin pulps increases yoghurt health benefits and could be scaled up further.

Biofunctionality of Probiotic Soy Yoghurt

Soybean provides health benefits such as reducing cardiovascular disease, reducing menopausal symptoms, weight loss, arthritis, diabetes, osteoporosis and brain function. It contains phytochemicals such as isoflavones, saponins, phytosterols that promote health benefits. Soy food products are perceived as healthy food and are considered an important part of the diet. More than 50% consumers in the USA agreed that soy foods are healthy foods. Soymilk is considered as a suitable economical substitute for cow’s milk and an ideal nutritional supplement for lactose-intolerant population and also considered cholesterol free product for cardiovascular disorders. Fermented soy milk is a good source of bioactive peptides such as anti-ACE, antioxidative, anti-cancer and immunomodulatory. Many fermented soy milk based products such as soy cheese, soymilk-kefir, soy yoghurt etc. are produced.

Characteristics of physico-chemical properties, volatile compounds and free fatty acid profiles of commercial set-type Turkish yoghurts

Ten most popular brands of commercial Turkish set-type yoghurts were collected from local retail outlets in Hatay, Turkey for two separate periods, and analyzed for basic nutrients, physico-chemical properties, volatile aroma compounds and free fatty acid profiles to compare their differences among the yoghurt products. The results showed that there were significant differences (P<0.05, 0.01, or 0.001) and variations in physico-chemical indices, volatile aroma compounds and volatile free fatty acid profiles among the yoghurt brands, which ultimately influence the flavor quality of the product. Acetaldehyde was predominant volatile compound in yoghurts, which followed by acetone, acetoin, diacetyl and ethanol. The level of diacetly was inversely related to titratable acidity, acetaldehyde and ethanoic acid. From ketones with high carbones 2-undecanone and 2-pentadecanone were higher than 2-butanone, 2-nanonane and 2-tridecanone. These ketones are related to fat content of yoghurt. Among short chain free fatty acids, ethanoic (acetic) acid was the most abundant in yoghurts, followed by hexanoic, octanoic and butanoic acids. These differences in detected chemical compositions of volatile compounds and free fatty acids would be applicable to predict flavor, nutritional value, quality control or shelf-life of the commmercial set-type Turkish yoghurts.

Evaluation of sensory properties and their correlation coefficients with physico-chemical indices in Turkish set-type yoghurts

Sensory properties and physico-chemical parameters of 10 most popular brands of commercial set-type Turkish yoghurts were evaluated and correlation coefficients between the two indices were investigated. The results indicated that increases in volatile compounds (acetaldehyde, 2-butanone, 2-nanonane, ethyl acetate), titratable acidity, ash and fat contents inversely correlated with the overall acceptability score of the yoghurt. However, diacetyl, C4 to C12 free fatty acids, pH, whiteness index and texture positively correlated with overall acceptability of the yoghurt products. It was concluded that the acceptability of the Turkish set-type yoghurts is mainly governed by the fifteen volatile compounds as well as the physico-chemical properties determined. Thus, the overall acceptability of the yoghurts was not influenced by a single characteristic, but rather by complex in nature.

Antioxidant, Some Flavor Components, Microbiological and Microstructure Characteristics of Corn Milk Yoghurt

Corn milk is considered as a new innovation especially in the making of yoghurt based products. The present study was conducted to study antioxidants components such as (phenols compounds and DPPH scavenging activity), total volatile free fatty acids, microbiological and microstructure characteristics in yoghurt samples produced from two different ratios of buffalos and corn milk (70:30 coded A and 60:40 coded B) respectively. Results indicated that the increasing ratio of corn milk led to increase the content of phenolic components and DPPH scavenging activity. Total viable content decreased in samples (70:30 and 60:40). Streptococci and lactobacilli count decreased by the increase of corn milk in produced samples. Results also show that the trend of yeasts content was the opposite ones. Election microscopy examination revealed that adding corn milk to yoghurt had more smoothly and systematically distributed casein with a bit coarse structure less porosity in the network of casein. From these results could be concluded that adding 40% corn milk during processing of yoghurt is increasing the antioxidant activity and improves the microstructure as well.

Optimization of a Tiger Nut-Based Yoghurt Formulation by Response Surface Methodology

Tiger nut is a comestible tuber which offers many under products such as yoghurt. The parameters influencing the quality of yoghurt being numerous, response surface methodology was used to optimize the formulation in order to reach a low intake of milk powder. The volume of tiger nut milk, mass milk powder and sugar mass are the factors monitored while the titratable acidity (AT), pH, dry soluble extract (ESS), ash, viscosity and color are the expected responses in these tests. The data are processed with a degree of confidence p < 0.05 associated with statistical analysis by the software Statgraphic Centurion XVI version 16.2.04. The different tests show that the factors have overall significant effects (p < 0.05) on the acidity, the ashes and the Whiteness index. The linear and quadratic factors of tiger nuts milk as well as those linears of the milk powder have significant effects (p < 0.05) on the pH and the ashes. The linear factors of milk powder have significant effects on DSE, AT and pH. The optimal formulation yielded a volume of tiger nut milk equal to 3.7 L/kg, a mass of powder milk of 63.4 g and 75 g of sugar for one kilogram of yogurt. With a desirability of 75%, this model is apt to explain the results and the experimental values fit with the predicted ones and are within the norms. The proximate analysis of optimal yoghurt formulation shows that fat and proteins contents are respectively 5.67% and 2.2%. Calcium, magnesium and potassium contents are respectively 160, 40 and 180 mg in 100 g of yoghurt.

Physicochemical and Organoleptic Characteristics of Manufactured Buffalo Milk Yoghurt Incorporated Soy and Corn Milks

Soy-corn-yoghurt is a fermented product that obtained from inoculation of yoghurt starter to soy corn milk. The present study was conducted to study the use of different ratios of soy corn milk and corn milk only with buffalo milk in the manufacture of yoghurt. Two experiments were carried out , the first experiment was 100 ml buffalo milk :soy corn milk ratios 90:10, 80:20, 70:30, 60:40 and 50:50 (w/w), the second was buffalo milk with Corn milk 90:10, 80:20, 70:30, 60:40, 50:50 and 40:60 respectively and 100% buffalo milk as control. Treatments were coded B1, C1, D1, E1 and F1 in the first experiment, while B2, C2, D2, E2, F2 and G2 for the second respectively. All treatments subjected to chemical and organoleptic assessment. It was found those pH, total protein, fat content were decreased with increasing the ratio of soy corn milk in the product. Also, increasing the ratio of corn milk led to decrease all the previously mentioned characteristics. Curd firmness values for yoghurt made from (70:30) coded D2 and (60:40) coded E1 were higher than that of other treatments. Results indicated that mixes of (50:50) coded F1, (60:40) coded E1 and mixes (90:10) coded B2, (80:20) coded C2 and (70:30) coded D2 had the highest sensory scores and chemical quality.

Effect of Okra Pectin on the Sensory, Physicochemical and Microbial Quality of Yoghurt

The objective of this work was to investigate the effect of okra pectin from two genotypes (asha and agbagoma) on the physicochemical, sensory and microbial quality of yoghurt. Okra pectin concentrations (w/w pectin to milk powder ratios) of 0.2%, 0.4% and 0.6% were used in the yoghurt preparation and its water holding capacity, titratable acidity and pH were analyzed against a control (0.0% pectin) weekly for a month. Consumer acceptability tests for the yoghurt samples were carried out using 50 untrained panellists on a 7-point hedonic scale. Total aerobic microorganisms present in the most preferred samples were enumerated over a four-week period. Results indicated that samples containing 0.2% asha pectin were most preferred by panelists. Water holding capacity varied significantly with those containing asha pectin higher than agbagoma counterparts and the control. There was a decline in pH with increasing pectin concentration and over the storage period. Samples containing agbagoma pectin had lower pH (3.60 - 4.32) compared to samples containing asha pectin (4.22 - 4.45). Titratable acidity increased during the storage period and with increasing pectin concentration. After four weeks of storage at 4°C sample containing 0.2% agbagoma pectin had the least microbial count (7.6 × 105 ± 4.51 cfu/g), followed by the sample containing 0.2% asha pectin (2.4 × 107 ± 11.14 cfu/g) and the control (8.6 × 107 ± 5.57 cfu/g). The study revealed that addition of okra pectin at 0.2% improved the consumer acceptability of yoghurt and 0.2% agbagoma pectin inhibits the proliferation of aerobic microbes. Addition of okra pectin also improved the water holding capacity and reduced whey exudation.

Antioxidant Activities of Exopolysaccharides Produced by Lactic Acid Bacteria Isolated from Commercial Yoghurt Samples

An antioxidant is a substance that inhibits the oxidation of other molecules caused by free radicals. The inbuilt antioxidant systems possessed by living organisms are generally not enough to prevent them from oxidative damages and the uses of synthetic antioxidants also have some harmful effects. This study was aimed at evaluating the antioxidant activities of exopolysaccharides produced by lactic acid bacteria isolated from yoghurt. Lactic acid bacteria (LAB) were isolated from six different brands of commercially available yoghurt using deMan Rogosa Sharpe (MRS) agar. The LAB isolates were identified based on morphological and biochemical analyses and were screened for exopolysaccharide (EPS) production. The LAB isolates screened positive were used for EPS production in a liquid medium and the EPS produced were purified and quantified using standard methods. Antioxidant activities of the EPS were evaluated by determining the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric ion reducing power, and total phenolic contents. Data obtained were analysed using Analysis of Variance. Total lactic acid bacterial count obtained from the yoghurt samples ranged from 0 - 3.9 × 104 CFU/mL with sample A (Fan Yoghurt) having the highest LAB count (3.9 × 104 CFU/mL). The isolated LAB and their incidence rate were Lactobacillus plantarum (25.49%), L. delbrueckii (19.61%), L. fermentum (15.69%), L. acidophilus (13.73%), Leuconostoc mesenteroides (11.76%), Lactococcus lactis (7.84%), and Lactobacillus casei (5.88%). Fifty-one out of the 64 LAB isolates were screened positive for EPS production and only six were able to produce substantial quantity of EPS ranging from 127.4 - 208.5 mg/L. The exopolysaccharides produced by L. fermentum had the highest DPPH radical scavenging activity (62.90%) while that of L. plantarum had the lowest (23.10%) at a concentration of 1000 μg/mL. Also, the EPS produced by L. fermentum recorded the highest ferric ion reducing power (12.89 mg AAE/mL) at 1000 μg/mL while that of L. plantarum had the lowest (5.62 mg AAE/mL). At 1000 μg/mL, the total phenolic contents of the EPS samples ranged from 1.41 - 1.58 mg GAE/mL, and the EPS produced by L. fermentum had the highest (1.58 mg GAE/mL) while those produced by L. paracasei had the lowest (1.41 mg GAE/mL). This study revealed that the exopolysaccharides produced by the LAB isolates showed high antioxidant activities with respect to their DPPH free radical scavenging activity, ferric ion reducing power and total phenolic contents.

Rare Case of Surviving Infant with Strawberry Yoghurt like Blood Diagnosed to Be Infantile Hypertriglyceridemia at 1 Month Old: A Case Report

Background: Hypertriglyceridemia in children means increased plasma fasting Triglyceride levels above the 95th percentile for age and sex. For children aged 0 to 9 years, a triglyceride level greater than or equal to 100 mg/dl is considered above the 95th percentile. Hypertriglyceridemia can be mild to borderline high, moderate to high, very high, severe and very severe (>2000 mg/dl). We present the case of a 1 month and 3 weeks old baby who presented with difficulty in breathing. It was accidentally found to have strawberry yoghurt like blood during phlebotomy, of which upon investigation had very high triglyceride levels of >2000 mg/dl. Case Presentation: 1 month and 3 weeks old female baby, admitted as referral from nearby health centre presenting with difficulty in breath, her blood sample was incidentally found to appear as strawberry yoghurt like. Clinically the infant had features suggestive of respiratory distress, with no other systemic abnormalities noted. Chest X-ray that was done had features of pneumonia. The working diagnosis on admission was Pneumonia, Electrolyte imbalance. The strawberry yoghurt like blood raised suspicions of hypertriglyceridemia. Our triglyceride levels in the infant were very high at 136 mmol/l (12,046 mg/dl). The patient was treated with IV antibiotics for pneumonia, electrolytes were corrected and Rosuvastatin was started. This patient improved remarkably and was discharged with Rosuvastatin. Lipid profile was followed up for 4 consecutive months in our outpatient clinic with a drastic drop in triglyceride and cholesterol. Conclusion: We report a case of infantile hypertriglyceridemia found accidentally during phlebotomy. Despite limited resource to evaluate further on primary cause of this condition as well as family’s poor economic status to seek further medical evaluation outside the country, this case report raises awareness on how to deal with this condition in a low resource setting. It also highlights the role of statins in the treatment of hypertriglyceridemia.

Apricot Probiotic Drinking Yoghurt Supplied with Inulin and Oat Fiber

In this study, the effects of different amounts of inulin and oat fiber addition on the properties of apricot probiotic drinking yoghurt (APDY) were investigated. Seven different APDY was produced. Six of them were produced by the addition of 0.5%, 1% and 2% inulin (B, C, D) and oat fiber (E, F, G) and one of them was produced as control sample. Pasteurized apricot pureed and sugar (10%) was added to fermented milk beverage. APDYs were analysed 1, 7, 14 and 21 days after production. Addition of fiber to APDYs had significantly affected on the pH, titratable acidity, water holding capacity, S. thermophilus, L. acidophilus Bifidobacterium BB-12 counts, and sensorial properties of the samples (p L. acidophilus and Bifidobacterium BB-12 counts increase by the addition of fiber into samples.

Some Properties of Probiotic Yoghurt Ice Cream Supplemented with Carob Extract and Whey Powder

In this study, some properties of probiotic yoghurt ice cream supplemented with carob extract and whey powder and viability of L. acidophilus and Bifidobacterium BB-12 on ice-cream were investigated. For this purpose 6 different ice cream was produced with different ratios whey powder and carob extract. The viable probiotic bacteria counts were determined on 1st, 7th, 30th, 60th and 90th days of storage. Addition of carob extract and whey powder significantly affected all properties of ice-creams. Results showed that the most positive effect on physical, sensory and microbiological properties was observed on sample D which produced with 1% carob extract and 1% whey powder addition.

Effect of rice fat mimics on texture and microstructure of low-fat yoghurt

This paper made a research on a new kind of rice fat mimics, which was obtained from rice powder hydrolyzed by α-amylase. Through the comparison between the yoghurt added with diverse proportions of above mentioned rice fat mimics and the reduced-fat yoghurt without any fat mimics as well as full-fat ones, the effect of the rice fat mimics in different proportions was examined upon the composition, the microstructure, the texture and the sensory evaluation of reduced-fat yoghurt. The results showed that the yoghurts added with rice fat mimics exhibited similar organoleptic attribute, textual characteristics and acceptability compared to those of full-fat controls （P〉0.05）, but with lower fat content and looser microstructures.

Application of Renneted Skim Milk as a Fat Mimetics in Nonfat Yoghurt

For a long time, fermented dairy products have been consumed for human’s nutrition and health. Recently, consumption of whole dairy products, such as full fat yoghurt, has declined due to the awareness of probable harmful effects of fat on consumers’ health, resulting change of market interest in favor of low or non fat dairy products. It is a challenge for food scientists to produce a suitable fat substitute providing the functionality of the missing fat. The present investigation was carried out to examine the effect of 0 to 50% renneted skim milk (RSM) as a fat mimetic upon the physico-chemical, physical, rheological and sensory characteristics of nonfat yoghurt in comparison to control samples (full fat and skim yoghurt). By increasing RSM content, the chemical characteristics (titratable acidity, pH as well as the content of fat and total protein) of yoghurts did not alter except decrease of total solid in sample with 50% RSM. The yoghurts with more content of RSM exhibited higher b*and a* values, while the highest L* value, viscosity, water holding capacity (WHC), firmness and lowest syneresis were found in sample containing 30% RSM. It seems that new interaction in gel network of yoghurts containing RSM, exhibited greater ability to bind water than control skim yoghurt. In addition, probably new bridges between milk proteins (interacting partially hydrolyzed casein with casein) can increase the number of bounds between protein particles leading to lower syneresis. However, excessive RSM content (higher than 30%) did not increase the L* value, viscosity and WHC of samples probably because of too much aggregation of casein. Sensory results revealed that sample containing 30% RSM was exactly alike to full fat yoghurt in terms of overall sensory attributes. New formulation of palatable skim yoghurt was developed using 3% RSM successfully.