Soy Yogurt Research Articles

Bioavailability of Ca, P and Zn and Bone Mineralization in Rats Fed Yoghurt and Soy-yoghurt Containing Bifidobacteria

Bioavailability of calcium, phosphorus and Zinc from probiotic dairy foods and other food sources has been an important issue of studies over recent years. The aim of the present study was designed to asses and to compare therapeutic effect of milk yoghurt and soy yoghurt containing bifidobacteria with regards to their effect on the bioavailability of Ca, P and Zn and bone mineralization in rats. Eight groups of rats were fed basal diet, cow milk, probiotic-free or probiotic-containing milk yoghurts (Bifidobacterium lactis Bb-12 or Bifidobacterium longum Bb-46), soymilk and soy-yoghurts containing only the above mentioned probiotics for 45 days. Upon feeding probiotic-containing milk and soymilk yoghurts, rat's serum Ca and P content were about two fold that of control and surprisingly the rat's serum Zn content was about 19-21 fold that of control. The increment of apparent absorption % as compared with control was ranged between 24.7–26.6, 24–38 and 51-70% for Ca, P and Zn, respectively. Original Research Article European Journal of Nutrition & Food Safety, 4(2): 110-126, 2014 111 The above mentioned results clearly demonstrate the enhancement of Ca, P and Zn bioavailability when probiotic diets were fed. A significant increase (n=6;p<0.05) was observed in ash content and breaking force of femur of rats fed probiotic milk-and soyyoghurts. Moreover probiotic milk yoghurts were much better than soy-yoghurts fermented by Bifidobacteria in enhancing bioavailability of Ca, P and Zn as well as bone mineralization. These results suggest that intake of probiotic milk-and soyyoghurts may be useful in enhancing mineral bioavailability and bone properties.

플레인 요구르트와 소이 요구르트의 미생물학적, 물리화학적 및 항산화 활성

양배추 피클로부터 분리된 유산균으로 발효하여 제조한 플레인 요구르트와 소이 요구르트를 저장하는 동안 미생물학적 및 물리화학적 변화와 항산화 특성을 조사하였다. 분리 균주는 당분해능과 유전자 염기서열 분석을 통해 L. casei PC05와 L. acidophilus PC16으로 동정되었다. Lactobacillus acidophilus PC16 균주로 발효시킨 요구르트의 적정산도, 점도 및 균수는 L. casei PC05 균주에 의해 제조된 요구르트에 비해 높게 나타났으며, 특히 플레인 요구르트보다 소이 요구르트에서 세균수와 물리화학적 요인의 측정값이 유의하게 높은 것으로 확인되었다. 한편, L. acidophilus PC16 균주로 발효시킨 요구르트는 DPPH 라디칼 소거능과 철이온 킬레이팅 활성이 높았으나, L. casei PC05 균주의 요구르트는 superoxide anion 제거능과 SOD 활성이 높은 것으로 나타났다. 대부분의 항산화능은 플레인 요구르트보다 소이 요구르트에서 더 높게 나타났으며, 요구르트의 지질과산화 억제능은 항산화 활성에 기인하는 것으로 추정된다. 또한 발효직후 요구르트의 미생물학적, 물리화학적 및 항산화 활성은 <TEX>$4^{\circ}C$</TEX>에서 8일간 저장하는 동안 거의 일정한 수준으로 유지되었다. This study evaluated the physicochemical and microbiological characteristics and antioxidant properties of yogurt samples fermented with lactic acid bacteria (LAB) obtained from pickled cabbage. API 50 CHL systems and 16S rRNA nucleotide sequence analyses revealed that the isolates were Lactobacillus casei PC05 and L. acidophilus PC16. Cell counts, titratable acidity, and viscosity of the yogurt samples fermented with L. acidophilus PC16 were significantly higher than those of the samples fermented with L. casei PC05 (P<0.05). The detected cell counts and physicochemical properties were significantly lower in plain yogurt than in soy yogurt (P<0.05). Yogurt samples fermented with L. acidophilus PC16 exhibited higher antioxidant activity, measured as ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and chelate ferrous ions, than those fermented with L. casei PC05. However, the ability to scavenge superoxide anions and superoxide dismutase (SOD) activity were significantly (P<0.05) higher in yogurt samples fermented with L. casei PC05 compared to those in samples fermented with L. acidophilus PC16. The antioxidant activity of soy yogurt was significantly (P<0.05) higher than that of plain yogurt. The antioxidant activity of the tested strains resulted in lipid peroxidation inhibition (in vitro), which may be related to the elimination of free radicals, chelating ability, and reducing power. There were no significant differences in the physicochemical properties and antioxidant activities of the yogurt samples during cold storage.

Tropical fruit pulps decreased probiotic survival to in vitro gastrointestinal stress in synbiotic soy yoghurt with okara during storage

The effect of mango and guava pulps on Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 viability in a soy yoghurt (SY) and on probiotic survival under simulated gastrointestinal conditions were investigated throughout 28 days of storage at 4 °C. The impact of fruit pulps on SY sensory acceptability was also assessed. Three formulations were produced from soymilk fermented with ABT-4 culture (La-5, Bb-12, and Streptococcus thermophilus) and supplemented with inulin and okara: SYC (control), SYM (with mango pulp), and SYG (with guava pulp). All formulations showed probiotic viabilities ranging from 8 to 9 log cfu/g, and fruit pulps did not affect the probiotic viabilities. However, the fruit pulps decreased probiotic survival significantly to simulated gastrointestinal stress. Acceptability was higher for SYM and this difference was significant at 21 days. Therefore, the improved acceptability of SY through the addition of fruit pulps might lead to a reduction in probiotic functionality.

Incorporation of soybean by‐product okara and inulin in a probiotic soy yoghurt: texture profile and sensory acceptance

This study evaluated the effect of inulin and okara flour on textural and sensory properties of probiotic soy yoghurt (SY) throughout 28 days of storage at 4 °C. Employing a 2(2) design, four formulations of SY produced from soymilk and fermented with an ABT-4 culture (Lactobacillus acidophilus La-5, Bifidobacterium animalis Bb-12 and Streptococcus thermophilus) were studied: SY-C (control); SY-I (with inulin); SY-O (with okara); SY-IO (with inulin + okara). The addition of okara and the refrigerated storage led to significant differences in the instrumental texture parameters of SY (P < 0.05). Inulin and okara did not affect SY sensory acceptability (P > 0.05), but there was a tendency for higher scores in the presence of inulin. On the other hand, the storage period, particularly at 21 days, was unfavourable regarding the acceptance of the different SY. The results showed that the addition of okara flour and the storage were significant factors to increase firmness of the soy yoghurts. SY acceptability was not affected by the incorporation of inulin or okara. These results suggest that okara, discarded as industrial waste, may be used in probiotic soy yoghurt, helping to increase the nutritional and functional properties without altering its acceptability.

Production of soy yogurt enriched with glyceollins

Soy milk was prepared from regular soybean (M1), soybean germinated for 3 days at 25°C (M2), and soybean germinated under fungal infection (M3). Rhizopus microsporus var. oligosporus ATCC 22959 was used as the elicitor for glyceollin production. Each soy milk was fermented with Streptococcus infantarius 12 and Weissella sp. 4 (1:5, v/v) for 12 h at 37°C. Significant induction of glyceollins was confirmed only in M3 soy milk and glyceollins maintained stably during 12 h fermentation period. The concentration of glyceollins in M3 yogurt was 2,400.4±83 and 2,525.2±158 μg/g dry matter (d.m.) at 0 and 12 h, respectively. The amount of daidzein was significantly higher in M3 yogurt (635.1±21) than that of M1 (417±11) and M2 (545±17 μg/g d.m.) yogurt in 12 h (p<0.05). M2 yogurt had the highest amount of genistein (695.3±17) followed by M3 (634.5±26) and M1 (612.5±14 μg/g d.m.) yogurt. M3 soy yogurt also showed the highest content of total phenolic compounds (5.37 mg/g) and antioxidant activity. The results indicated that functional soy yogurt can be prepared from soybean enriched with glyceollins.

Production of Soy yoghurt from Lactobacillus isolated from fermented African Oil Bean Seed (Ugba)

Production of Soy yoghurt from Lactobacillus isolated from fermented African Oil Bean Seed (Ugba)

α-Galactosidase Activity and Oligosaccharides Utilization by Lactobacilli during Fermentation of Soy Milk

In this study, α-galactosidase activity and depletion of oligosaccharides by six standard probiotic lactobacillus cultures were evaluated under at incubation times (6, 12, 18, 24, 30 h) in soy milk medium fortified with whey protein concentrate (WPC70) at 1.5%. Reduction of stachyose was higher due to maximum production of α-galactosidase (α-gal) enzyme (133.65 U/mg) by Lactobacillus rhamnosus C6 as compared with the other Lactobacillus cultures and was highest at 30 h of incubation (3.03 mg/100 mL). The results of this study will allow selection of L. rhamnosus C6 culture in soy milk medium supplemented with whey protein concentrate (WPC70), which will enhance growth of Lactobacillus and also reduce whey separation during fermentation process. This culture also showed highest proteolytic activity (381.67 μg serine/mL) by hydrolyzing soy proteins and produce soy bioactive peptides, which have health beneficial activities. L. rhamnosus C6 strain showed maximum α-galactosidase production as well as reduction of oligosaccharides viz. raffinose, stachyose and sucrose mostly present in soy milk. However, Lactobacilus casei NCDC17 also exhibited similar activity during soy milk fermentation. WPC70 fortification enhanced bacterial growth providing nutrition to the bacteria and also increased physiological activity during fermentation in soy milk medium. These two strains can be selected for the development of functional soy foods like soy yoghurt, soy cheese, soy beverages and soy dahi.

Effect of Synbiotic Interaction of Fructooligosaccharide and Probiotics on the Acidification Profile, Textural and Rheological Characteristics of Fermented Soy Milk

Preparation of yoghurt-like product from non-dairy raw material, such as soy with probiotic and prebiotic is a novel development in the field of fermented functional foods. This research work aimed at finding the new combinations of probiotics Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus, which can give good product characteristics to fermented soy milk. Fructooligosaccharide was added in an attempt to reduce the after-taste of soymilk, improve acidification rates and growth of probiotics. Acidification rate was enhanced with L. acidophilus–L. plantarum and L. acidophilus–L. plantarum–L. rhamnosus, resulting in a shorter time to reach pH 4.5. Hardness was significantly (P < 0.05) higher for soy yoghurt fermented by binary co-culture followed by mixed cultures. All the samples showed higher G′ (1,279.70–1405 Pa) and lower tan δ (0.273–0.346) values which signifies firmer and solid-like character of the gel formed by probiotic bacteria. Soy yoghurt made with L. acidophilus–L. plantarum resulted in improved product characteristics with shorter t pH 4.5 (4.28 h). Soy yoghurt fermented with L. acidophilus–L. plantarum showed more than 9 log cfu/ml count which is required for probiotic functional food.

Nutritional evaluation of soy yoghurt in comparison to soymilk and commercial milk yoghurt. Effect of fermentation on soy protein

Soymilk was fermented using Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. The soy yoghurt produced was evaluated in comparison to soymilk and commercial milk yoghurt by biological evaluation, rat growth, nitrogen balance assays and microbiological methods. Trypsin inhibitor activity and chemical composition were also determined for all samples. For the soy yoghurt, the growth and nitrogen balance values were not different from the control diet, but the nitrogen balance values were higher than for the soymilk, without significant difference in terms of growth assays. Compared to the commercial yoghurt, Net Protein Ratio and Nitrogen Utilization values were lower, but the Protein Efficiency Ratio, Biological Value and Net Protein Utilization values were equivalent, and for digestibility assays the best results were obtained with the soy yoghurt. The results indicated that soy yoghurt represents a good protein alternative to milk yoghurt and casein. The protein quality of soymilk ...

Effect of Different Concentrations of Coconut Milk on the Chemical and Sensory Properties of Soy-coconut Milk Based Yoghurt

Abstract The possibility of enhancing the sensory attributes of soy yoghurt through the use of composite soymilk was investigated. The effect of using starter cultures from different sources on the chemical characteristics and consumer ac-ceptability was also studied. Soy milk containing 0, 10 and 20% coconut milk were used in the production of soy yoghurt using commercially available yoghurt starter and starters isolated from naturally fermenting soy milk and cow milk. Chemical and sensory characteristics of soy yoghurts obtained were evaluated. The pH of the yoghurt premixes at the be-ginning of fermentation ranged between 6.25 and 6.45; after fermentation the values were between 4.81 and 5.51 with commercially availab le starter bringing about greatest pH reduction. Chemical compositions of obtained soy yoghurts were as follows: titratable acidity as %lactic acid (0.25-0.43%), crude protein (2.66 -3.62%), fat content (0.13 -0.89%), total solid content (7.91-9.06%). Variation in premix formulation had no significant (P>0.05) effect on the chemical composition of different soy yoghurts obtained. Addition of coconut milk to soy milk improved the sensory characteristics of soy yoghurts with the premix containing 10% coconut milk fermented with starter obtained from cow milk producing yoghurts with the best taste, aroma, and acceptability. Results from the present study have demonstrated a further way of enhancing soy yo-ghurt acceptability by the western ‘palate’.

Validation of Sojasun®, a soy‐based fermented dessert, as an efficient source of calcium

Aging is associated with increased bone turnover and bone loss, mainly in menopausal women in relation with oestrogen deficiency. Women with low calcium (Ca) intake are at greater risk for bone loss. Soy products are naturally low Ca content, but often fortified with Ca at a level equivalent to many dairy foods. A double blind, randomized parallel‐arm clinical trial was carried out to compare the effects of calcium naturally present in yogurt vs. a calcium‐fortified soy‐based fermented dessert (Sojasun® containing Lipocal®, triphosphate Ca encapsulated with lecithin) on bone metabolism in early menopausal women (N = 44). Subjects consumed study products three times a day for 12 weeks. Both dairy and soy yoghurts contained 150 mg Ca per serving. Bone metabolism parameters (BALP for formation and CTX as a marker for resorption) were evaluated at baseline and end of treatment. A decline in bone turnover was noticed in the 2 groups, as observed by a decrease in bone parameters in both groups. No statistical differences were observed after 12 weeks of consumption, suggesting that both sources of calcium were equivalent. Supplementation with calcium seems to limit bone metabolism turnover, as shown by the reduction in bone metabolism parameters in both groups.

Effects of Soy Yogurt on Intestinal and Plasma Polyamine Levels in Adult Rats

Polyamines are important constituents of all mammalian cells. We previously found that polyamines in soy yogurt, a mixture of fermented soymilk and okara, absorbed easily in the small intestine of growing rats, but the polyamine level in plasma scarcely increased. The level of polyamine in the body tends to decrease with age. In the present study, we investigated changes in polyamine levels in the intestines and plasma of adult rats to clarify the effect of soy yogurt in supplying polyamine to the plasma in adult rats. The polyamine levels in the intestine and plasma of adult rats increased significantly after ingestion of soy yogurt. It was found that soy yogurt is useful for the recovery of polyamine in adult rats.

Analysis of 20 trace and minor elements in soy and dairy yogurts by ICP-MS

The content of 20 trace and minor elements in soy and dairy yogurts consumed in Spain has been determined using inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. This work presents two goals: a) to determine the nutritional value in terms of minor elements content, using recommended daily allowance data; b) to determine the levels of trace toxic elements and compare them with the acceptable daily intake values. The developed analytical method was validated by using both milk certified reference materials and recovery experiments over different yogurt samples, obtaining satisfactory results in all cases. In addition, a comparison between the levels of minor elements found in soy and dairy yogurts was performed. Much higher concentrations of Cu and Mn were found in soybean products (up to 30-fold higher) and minor differences were observed in the content of Fe and Zn. Other minor element found at higher concentrations in soy yogurts was Ni (effect usually observed in plant-origin foods), which was determined at levels up to 450ngg−1 in some samples. Finally, the levels of toxic elements were very low, even below the detection limit in some cases.

Effect of ingestion of soy yogurt on intestinal parameters of rats fed on a beef-based animal diet

The aim of this study was to investigate whether the ingestion of soy yogurt fermented with Enterococcus faecium CRL 183 would modify the intestinal count of enterococci, fecal pH and ammonia content in rats fed on a diet containing red meat. The rats were placed in 4 groups: for 60 days, group I was given a standard casein-based rodent feed and groups II-IV, the beef-based feed. From day 30, groups III-IV also received the following products: III) soy yogurt; IV) suspension of E. faecium CRL 183. At the start and on days 30 and 60, feces were collected for the determination of pH, ammonia content, count of enterococci and identification of their species. On day 60, rats were sacrificed and their colons also removed for count of enterococci and identification of their species. Rats that ingested soy yogurt showed no significant change (P<0.05) in fecal counts of Enterococcus spp., but, this rat group showed a higher count of E. faecium than rats that ingested suspension of E. faecium CRL 183. The ingestion of soy yogurt and E. faecium culture caused a significant rise (P < 0.05) in fecal pH and ammonia content. Our results suggest that consumption of soy yogurt fermented with E. faecium CRL 183 and L. helveticus subsp. jugurti could change the species of Enterococcus spp. present in the feces and colon of rats fed on a beef-based diet. However, the fermented soy product and the pure culture of E. faecium CRL 183 also induced undesirable effects such as the increase of fecal pH and ammonia content in the feces of rats fed on a beef-based diet.

Effect of ingestion of soy yogurt on intestinal parameters of rats fed on a beef-based animal diet

The aim of this study was to investigate whether the ingestion of soy yogurt fermented with Enterococcus faecium CRL 183 would modify the intestinal count of enterococci, fecal pH and ammonia content in rats fed on a diet containing red meat. The rats were placed in 4 groups: for 60 days, group I was given a standard casein-based rodent feed and groups II-IV, the beef-based feed. From day 30, groups III-IV also received the following products: III) soy yogurt; IV) suspension of E. faecium CRL 183. At the start and on days 30 and 60, feces were collected for the determination of pH, ammonia content, count of enterococci and identification of their species. On day 60, rats were sacrificed and their colons also removed for count of enterococci and identification of their species. Rats that ingested soy yogurt showed no significant change (P<0.05) in fecal counts of Enterococcus spp., but, this rat group showed a higher count of E. faecium than rats that ingested suspension of E. faecium CRL 183. The ingestion of soy yogurt and E. faecium culture caused a significant rise (P < 0.05) in fecal pH and ammonia content. Our results suggest that consumption of soy yogurt fermented with E. faecium CRL 183 and L. helveticus subsp. jugurti could change the species of Enterococcus spp. present in the feces and colon of rats fed on a beef-based diet. However, the fermented soy product and the pure culture of E. faecium CRL 183 also induced undesirable effects such as the increase of fecal pH and ammonia content in the feces of rats fed on a beef-based diet.

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.

Quality Attributes of Soy-yoghurt During Storage Period

The utilization of soybean milk in manufacturing yoghurt in Sudan was investigated. Soybean milk was prepared from grinded soybean seeds. Four samples of soy yoghurt product were used, namely sample A) 100% soymilk (sample B) 1:1 soymilk: cow milk), sample C (2:1 soymilk: cow milk) and sample D (1:2 soymilk: cow milk). The prepared soy yoghurt samples were stored at refrigerator temperature (10±2 C) o followed by analyses at 0, 5, 10, 15 and 20 days intervals. The chemical compositions of soybean milk used were the total solids (13.15%), protein (7.64%), fat (2.75%), pH-value (6.70) and titratable acidity (0.20%).The type of milk significantly (p<0.05) affected the pH-value of the soy yoghurt. Sample A was the highest (4.50), sample D the lowest (3.30) while sample B and sample C were at an intermediate position (3.50 and 3.70 respectively). Storage period significantly (p<0.05) affected the pH-value of soy yoghurt, the highest value (4.30) was obtained at the beginning of the storage period, while the lowest value (3.00) at the end. The type of milk significantly (p<0.05) affected the titratable acidity of the soy yoghurt. Sample A was the lowest (1.12%), Sample D was the highest (2.50%), while samples B and C were in an intermediate position. Storage period significantly (p<0.05) affected the titratable acidity of soy yoghurt. The lowest titratable acidity (1.21%) was obtained at the beginning of storage period and the highest (2.60%) at the end. The type of milk significantly (p<0.05) affected the wheying off of the soy yoghurt. Sample A was the highest (2.70 ml), sample D was the lowest (1.70 ml), while samples B and C were at an intermediate position. Storage period significantly (p<0.05) affected the wheying off of soy yoghurt. The lowest wheying off (0.00 ml) was obtained at the beginning of storage period and the highest (4.00 ml) at the end. The chemical analyses of soy yoghurt samples at zero time processing, sample A) 100% soymilk (was the highest (31.20%) for total solids and protein content (16.70%),while sample D (1:2 soymilk: cow milk) was the lowest (15.70%) for total solids and protein content) 11.25). Sample B and C were at an intermediate position. Sample A was the lowest (2.20%) for fat content, sample D was the highest (3.25%),while samples Band C occupy an intermediate position. The sensory evaluation significantly (p<0.05) affected by The type of milk and storage period revealed that, the best score (p<0.05) in appearance (4.38), flavour (4.10), texture (4.22) and overall acceptability (4.28) in sample D(1:2 soymilk: cow milk), the worst was recorded by sample A (Soymilk 100%) for appearance (2.68), flavour (3.48), texture (3.36) and overall acceptability (3.44). The other samples were at an intermediate position. It was found that 10 days storage period at refrigerator temperature (10±2 C) was quite satisfactory o to attain good quality soy yoghurt.

Cultural differences in food description and preference: Contrasting Vietnamese and French panellists on soy yogurts

This study investigated the cultural differences in description and preference of soy yogurts formulated for French market between French and Vietnamese panellists, two cultures with important differences in soy and dairy product consumption habits. Two trained panels assessed the in-mouth perceptions of eight soy yogurts and four milk yogurts, using a conventional descriptive analysis method. Three soy and two cow milk yogurts, representing the sensory space of the product set were then assessed by two consumer panels in a hedonic test. A multiple factor analysis (MFA) showed that the two sensory profiles are highly similar. The two panels agreed on texture and taste attributes but cultural specificities were revealed for aroma attributes: French panellists used two times more attributes than Vietnamese panellists (10 vs. 5). While the Vietnamese attributes are related to soy-based products (“ raw soybean”, “ soy milk” and “ tofu”) the French attributes were more diverse and even included references to non-food products (“ wood”, “ earthy” and “ chalk”). The result of the hedonic test showed that soy yogurts were worst appreciated by both panels. In general, the soy and dairy product consumption data of the panellists helped to explain their preferences towards soy or milk yogurts. However this is not the case of a Vietnamese consumer subgroup who consumes soy products frequently. Their hedonic ratings on soy yogurts suggest that they expected the authentic soy-related sensory properties in tasting soy yogurts and these properties might not be found in this new product.

Physicochemical and sensory characteristics of soy yogurt fermented with Bifidobacterium breve K-110, Streptococcus thermophilus 3781, or Lactobacillus acidophilus Q509011

The physicochemical and sensory characteristics of soy yogurt fermented with Bifidobacterium breve K-110, Streptococcus thermophilus 3781, or Lactobacillus acidophilus Q509011 for 36 hr at 37°C were investigated and the soyasaponin metabolites of soy yogurt were measured. L. acidophilus reduced the pH of soy yogurt on day 0 to optimum level. After 36 hr, the Brix dropped to 8.48–9.12°Bx. The viable cell counts of soy yogurts on day 0 were 8.43 to 9.01 log CFU/mL. Among starters, B. breve alone produced soyasapogenol B, although it was not detected in non-fermented soybean. B. breve produced poor sensory scores in all sensory aspects. By mixing B. breve with S. thermophilus and L. acidophilus, the sensory scores of B. breve could be improved. These findings suggest that the mixed culture of S. thermopilus or L. acidophilus with B. breve may be an ideal starter for the preparation of soy yogurt.

Effect of Soy Yogurt (Lactic Acid-Fermented Okara in Soymilk) on Intestinal Polyamine Level in Rats

Polyamines, putrescine, spermidine and spermine, are important constituents of all mammalian cells and are essentially involved in a variety of regulatory step during normal and malignant cell proliferation. Okara and soymilk fermented with Lactobacillus were combined to form soy yogurt, which is rich in polyamine content. We investigated the effect of soy yogurt on polyamine levels in intestines and blood of rats. The ingestion of soy yogurt induced the increase of mucosal polyamine level in small intestine. Although the polyamine level in cecum was increased by the ingestion of soy yogurt, the polyamine levels in large intestine and blood were not increased. It was found that the ingestion of polyamine-rich soy yogurt could affect the polyamine level in only small intestinal mucosa. The large intestine seems to regulate the polyamine level to prevent own cells from hyperproliferation. It was assumed that blood kept polyamine level constant in spite of the level changes in intestines.