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1.
对不同品种和产地的菊芋主要成分进行了测定,并利用乳酸菌对菊芋汁进行发酵,研究了不同乳酸菌在菊芋汁中的生长规律、低温存活性及发酵菊芋汁中主要风味物质。结果表明,4种乳酸菌在菊芋汁中均生长良好,最高活菌数可达到109CFU/mL;菊芋汁经乳酸菌发酵后具有良好风味,其风味的差异与发酵菌种有关;发酵菊芋汁中乳酸菌在4℃低温贮藏过程中具有较好的低温存活性,4周后活菌数保持在108CFU/mL。菊芋汁适用于开发成新的功能性乳酸菌饮料。  相似文献   

2.
The yeast flora in samples of 13 different whole-crop maize silages was shown to be predominated by Candida krusei, C. lambica, Saccharomyces dairensis, S. exiguus, C. holmii or C. milleri. All these strains fermented glucose but, except for the latter three species, not sucrose, α-trehalose or raffinose. Under conditions resembling those in silage, i.e. at pH 4.0 in the presence of a complex nitrogen source, all strains assimilated lactic and acetic acids. This result suggests that the predominant yeasts in silage should not be distinguished into lactate utilisers and lactate non-utilisers. All strains, except those of Saccharomyces dairensis, tolerated acetic acid (5 g litre?1) and grew at pH 4.0 in a mineral salts medium containing lactic acid (10 g litre?1), acetic acid (5 g litre?1) and yeast extract (1 g litre?1). Growth in this medium was completely inhibited by the cationic detergent Arquad C33W (20 mg litre?1), propionic acid (5 g litre?1), benzoic acid (5 g litre?1) or salicylic acid (10 g litre?1).  相似文献   

3.
BACKGROUND: Theanine, a unique amino acid found almost exclusively in tea plants, has various favourable physiological and pharmacological functions in humans. Gamma‐glutamyltranspeptidase (GGT, EC 2.3.2.2) is considered to be the most effective enzyme for the production of theanine. In fact, GGT can catalyse the transfer of γ‐glutamyl moieties from γ‐glutamyl compounds to water (hydrolysis) or to amino acids and peptides (transpeptidation). RESULTS: A novel strain, SK11.004, which produces GGT with high theanine‐forming ability was isolated from fermented shrimp paste and identified as Bacillus subtilis through its physiological and biochemical properties as well as its 16S rDNA sequence analysis. Theanine (18.9 mmol L?1) was synthesised by GGT (0.06 U mL?1) through transfer reaction in the presence of glutamine (20 mmol L?1) as a donor and ethylamine HCl (50 mmol L?1) as an acceptor at pH 10 and 37 °C for 4 h, the conversion rate being up to 94%. CONCLUSION: The enzymatic synthesis of theanine using GGT from a newly isolated strain Bacillus subtilis SK11.004 was found to be an efficient method. Moreover, compared with others, the GGT from B. subtilis SK11.004 exhibited the highest ratio of transferring activity to hydrolytic activity using glutamine, suggesting a high potential application in the production of theanine and other functional γ‐glutamyl compounds. Copyright © 2010 Society of Chemical Industry  相似文献   

4.
Weaned pigs were fed diets with added Jerusalem artichoke for 28 days. In a first trial, the pigs received raw tubers in addition to their normal ration. In a second trial, the pigs received dried Jerusalem artichoke (10–60 g kg-1) in the diet. Pigs eating the raw tuber had significantly increased body weight gains due to the consumption of the raw tuber, but significantly decreased feed efficiency. Adding dried Jerusalem artichoke to the diet significantly increased weight gains. Feed efficiency was improved, but not significantly. Faecal valeric acid concentration was significantly increased in animals eating Jerusalem artichoke.  相似文献   

5.
This study investigated the effect of initial sugar concentrations (°Brix of 17, 23 and 30) on mango wine composition fermented by Saccharomyces cerevisiae MERIT.ferm. It was found that growth rate and maximum cell population were inversely correlated with initial sugar levels with the fastest growth rate and largest cell population in the low sugar fermentation. However, the cell population in the low and medium sugar fermentation declined significantly (from 8.7 and 8.2 log to 2 and 2.8 log, respectively) relative to the high sugar fermentation in which cell populations remained stable upon reaching the stationary phase (7.7 log). Glycerol production increased with increasing sugar content in low (13.4 g L?1), medium (14.5 g L?1) and high (15.9 g L?1) sugar fermentation. In addition, high sugar fermentation had a negative impact on volatile production with significantly lower amounts of acetate esters (1.5 mg L?1) but more acetic acid (0.54 g L?1) compared to the low (5.0 mg L?1 and 0.44 g L?1, respectively) and medium (3.7 mg L?1 and 0.49 g L?1, respectively) sugar fermentations. Furthermore, volatiles especially terpene hydrocarbons (α‐caryophyllene was released) present in mango juice were significantly metabolised after fermentation, while numerous new volatile compounds (such as isobutyl alcohol, isoamyl alcohol, ethyl and acetate esters) were produced. Some terpene alcohols were released and converted into corresponding acetyl esters. This may indicate that the mango wines fermented with different levels of sugars would have different flavour aromas.  相似文献   

6.
BACKGROUND: The presence of phenolics in fruit, red wine and vinegar has positive health effects due to their significant antioxidant activity. The aim of the study was to determine the effects of two different vinegar production methods on antioxidant activity and phenolic level of vinegars derived from Ulugbey Karasi grapes. Traditional surface and industrial submerge methods were used to make vinegar. Samples were taken from fresh red grape juice, maceration, wine, traditional vinegar and industrial vinegar. RESULTS: Total phenolic content of traditional and industrial vinegar samples were 2690 mg L?1 and 2461 mg L?1 GAE, respectively. ORAC values of traditional and industrial vinegar samples were 10.50 µmol mL?1and 8.84 µmol mL?1 TE, respectively. Antioxidant activity values of traditional and industrial vinegars were 13.50 mmol L?1 and 10.37 mmol L?1 TEAC, respectively. Gallic acid, catechin, epicatechin, chlorogenic acid, caffeic acid, syringic acid, p‐coumaric acid and ferulic acid were detected in grape juice, wine and vinegar samples. The content of catechin in industrial vinegar (27.50 mg L?1) was significantly higher than that of in traditional vinegar (13.76 mg L?1) (P < 0.05). Traditional vinegar had higher amounts of chlorogenic and syringic acids than the industrial vinegar (P > 0.05). CONCLUSION: Results of this study showed that different production methods affected the functional constituents of wine vinegars. Copyright © 2010 Society of Chemical Industry  相似文献   

7.
BACKGROUND: ?liwowica ??cka is a strong, distilled, home‐made plum brandy produced in a submontane region of Poland. The aim of the present study was to determine the chemical composition of this alcoholic beverage (samples from the years 2001–2004) and compare it with that of other plum brandies. Gas chromatography and spectrophotometry methods were used to detect major volatile components. RESULTS: Home‐made Polish plum brandies generally contained more ethanol (64.7–72.5% v/v), methanol (5.59–8.74 g L?1100°) and butanol (32–335 mg L?1100°) and less isobutanol (406–491 mg L?1100°), pentanol (4.3–14.9 mg L?1100°) and 2‐phenylethanol (61–68 mg L?1100°) than other samples. The amyl alcohols/1‐propanol and isobutanol/1‐propanol ratios might be used as indices to distinguish spontaneously fermented plum brandies from those produced by monoculture. Statistically significant differences (P < 0.01) were found in the plum brandy sensory characteristics examined. Total sensory scores of Polish plum brandies ranged between 12.0 and 14.3, while Slovakian Slivovica received the highest score (16.7). CONCLUSION: The results showed that plum brandies produced in the ??cko area are characterised by a similar and original chemical composition that results mainly from spontaneous fermentation as well as traditional production technology. Copyright © 2007 Society of Chemical Industry  相似文献   

8.
Caxiri is a fermented alcoholic beverage made from cassava, corn and sweet potatoes by indigenous people in Brazil. Saccharomyces cerevisiae Rhodotorula mucilaginosa, Lactobacillus fermentum, Bacillus subtilis and L. helveticus were the main microbial species detected. Maltose was the main carbohydrate found (19.12 g L?1), and lactic acid (15.09 g L?1) and ethanol (92.16 g L?1) were also found in high concentrations. Gas chromatography‐flame ionisation detector was used to identify thirteen volatile compounds. Among these volatiles, the higher concentrations were decanoic acid (123.04 μg L?1) for the acids, diethyl malate (88.32 μg L?1) for the esters, furfural (109.31 μg L?1) for the aldehydes, 2‐phenylethanol (1022.76 μg L?1) for the alcohols and 1,1‐diethoxyethane (226.24 μg L?1) for the others. This study contributes to increasing knowledge of the microbiota present in the alcoholic fermentation produced from cassava, corn and sweet potatoes.  相似文献   

9.
A total of fifty‐six strains of lactic acid bacteria isolated from Chinese sauerkraut juice from Shenyang were screened for glucansucrase production. Among them, strain DRP105 was detected to produce highest yield of glucansucrase in MRS broth, which was identified to be Leuconostoc mesenteroides. Based on Plackett–Burman Experiment, sucrose, sodium acetate and initial pH were found to be the most significant factors for glucansucrase production of L. mesenteroidesDRP105. Afterwards, effects of the three main factors on glucansucrase activity were further investigated by central composite design, and the optimum composition was sucrose 35.74 g L?1, sodium acetate 6.46 g L?1 and initial pH 5.90. Optimum results showed that glucansucrase activity was increased to 6.26 ± 0.09 U mL?1 in 24 h fermentation, 33.19% higher than before. Our study also suggested that Tween 80 and dextran have potential to improve glucansucrase stability at temperature (30 °C) higher than enzyme storage temperature in crude fermented broth.  相似文献   

10.
In this study, a total of forty‐five strains of lactobacilli and streptococci were determined exopolysaccharide (EPS) production in skim milk and Man Rogosa and Sharpe (MRS)/M17 medium, viscosity and proteolytic activity. The exopolysaccharide production by lactobacilli strains during growth in MRS medium was twenty‐one to 211 mg L?1, while in skim milk was to thirty‐six to 315 mg L?1. The EPS production by streptococci strains during growth in M17 medium was sixteen to 114 mg L?1, while in skim milk was to twenty‐four to 140 mg L?1. The EPS production of strains was lower in MRS/M17 medium than skim milk. Results showed that it was not clear correlation between the viscosity and EPS production of some strains. All strains were shown proteolytic activity. Positive correlations between exopolysaccharide production and proteolytic activity in skim milk were found some strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. These results indicated that the high exocellular protease‐producing strains can produce high EPS in skim milk. The monomer compositions of the EPSs formed by selected five strains were analysed. Mannose dominated (99–100%) on the EPS produced by L. delbrueckii subsp. bulgaricus and S. thermophilusstrains (except L. delbrueckii subsp. bulgaricus 22) in skim milk and MRS/M17 medium. Besides, the EPSs of strains in skim milk contained small amount of lactose.  相似文献   

11.
BACKGROUND: The aim of this study was to determine whether the consumption of soy product fermented with Enterococcus faecium CRL 183, would modify the fecal microbiota of rats fed a diet containing red meat. The rats were placed in groups, distinguished by their diets. For 60 days, group I was given a standard casein‐based rodent feed and groups II–VI, the beef‐based feed. From the 30th day, groups III–VI also ingested the following products: group III, E. faecium‐fermented soy product; group IV, pure suspension of E. faecium; group V, sterilized fermented soy product; and group VI, unfermented soy product. RESULTS: Rats that ingested fermented soy product showed a slight increase in the numbers of lactobacilli (0.45 log CFU g?1), as did the casein‐based diet group (0.47 log CFU g?1). The fermented soy product did not cause any reduction in the number of enterobacteria or clostridia, but promoted a slight fall in the viable count of Bacteroides spp. (2.80 ± 0.20 to 2.34 ± 0.07 log CFU g?1). CONCLUSIONS: The results indicate that the ingestion of this fermented soy product did not lead to significant changes in the fecal microbiota of the rats fed on a beef‐based diet. Copyright © 2009 Society of Chemical Industry  相似文献   

12.
Lipid quality and fatty acid compositions of fish oils recovered from fish (Sea bass – Dicentrarchus labrax) waste silages produced with formic acid (FA) and five different LAB strains (Lactobacillus plantarum (LP), Pediococcus acidilactici (PA), Enterococcus gallinarum (EG), Lactobacillus brevis (LB) and Streptococcus spp. (ST)) were assessed to ensure for the usage for human consumption. Generally, it was observed that there were no significant differences between PUFA contents (23.27–23.64%). Peroxide (PV) (2.12 meq active O2/per kg of oil) and TBA values (1.07 mg malonaldehyde (MA) g?1 oil) of fish oils from acid silage were significantly higher than those of the fermented ones (1.14–1.91 meq active O2 kg?1, 0.67–0.81 mgMA g?1 oil, respectively). Anisidine values (AV) were determined in range of 8.04–11.14 for fermented silages and 13.08 from acid silage. The highest totox value (17.33 ± 0.88) was also detected in acid silage oil whereas fermented groups gave totox value in the range of 10.40–13.88. It can be concluded that the initial lipid quality of fermented fish waste silages was better than the initial lipid quality of acid fish waste silage. Therefore, fish oils recovered from fermented silages can be used as food additives or supplements for animal and human diets.  相似文献   

13.
BACKGROUND: Hydroponic culture was used to investigate the effect of NaCl concentrations on the growth, nutrient uptake, phenolic content and antioxidant activity of Salvia officinalis L. leaves. The antioxidant capacity of the methanolic extract of S. officinalis was evaluated by using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging test and β‐carotene‐linoleic acid bleaching assay. Physiological and biochemical parameters of S. officinalis were assessed after 4 weeks of salt treatment with 0, 25, 50, 75 and 100 mmol L?1 NaCl. RESULTS: Plant growth exhibited a reduction of 61% at 100 mmol L?1 NaCl. Assessment of Na+, K+ and Ca2+ and water contents of shoots and roots showed that S. officinalis is able to regulate Na+ concentration by active compartmentation in vacuoles. Salvia officinalis phenolics were increased in response to salinity at the threshold of 75 mmol L?1 NaCl. This herb was also found to be able to achieve important DPPH? quenching activity and to inhibit the β‐carotene‐linoleic acid bleaching notably enhanced by salt treatment. It is interesting to highlight the correlation between the phenolic and antioxidant activity, suggesting the involvement of these compounds in this activity. CONCLUSION: Salvia officinalis treated with 75 mmol L?1 NaCl constitutes a potential source for production of secondary metabolites useful in several applications. Copyright © 2011 Society of Chemical Industry  相似文献   

14.
A simple spectrophotometric method was developed for the analysis of inulin in Jerusalem artichoke tubers. The inulin was extracted from the artichoke tuber samples using accelerated solvent extraction method, before subsequent hydrolysis in acid condition. The hydrolysates were then analyzed for fructose using spectrophotometry. The spectrophotometric method is based on oxidation of fructose by periodate and evaluation of the remaining periodate by measuring the absorbance at 350 nm of the tri-iodide complex formed, upon addition of potassium iodide. The optimum conditions for the detection of fructose were 0.1 mmol L−1 periodate and 1.5 mmol L−1 potassium iodide at pH 6.0. The proposed method was validated for its analytical performance parameters including accuracy, precision, and recovery. The method was applied to the determination of inulin in ten varieties of Jerusalem artichoke grown in the northeastern part of Thailand. The inulin content in the samples was found to be in the range of 63–75.5% dry weight, and the degree of polymerization was in the range of 14–20. The inulin contents obtained from the proposed spectrophotometry were not significantly different (p = 0.05) from those obtained from high-performance anion-exchange chromatography coupled with pulsed amperometric detection. The results indicated that the present spectrophotometric method can be used as an alternative to chromatographic analysis for the determination of inulin in plant samples.  相似文献   

15.
BACKGROUND: Angiotensin I‐converting enzyme (ACE) is a dipeptidyl carboxypeptidase associated with the regulation of blood pressure. ACE inhibition results in a lowering of blood pressure. Lactic acid bacteria are known to produce ACE inhibitors during fermentation. Fermented camel milk is the main traditionally fermented dairy food for desert nomads. The beneficial effects of fermented camel milk, which include the prevention of such diseases and conditions as gastroenteritis, tuberculosis and hypertension, have been demonstrated experimentally. RESULTS: ACE inhibitory activity was observed in fermented milk containing Lactobacillus helveticus 130B4, a strain isolated from traditionally fermented camel milk. The peptide that inhibited ACE was purified from the fermented milk by reverse‐phase high‐performance liquid chromatography. The amino acid sequence of the peptide was identified as Ala‐Ile‐Pro‐Pro‐Lys‐Lys‐Asn‐Gln‐Asp (IC50 = 19.9 µmol L?1). The same Ala‐Ile‐Pro‐Pro‐Lys‐Lys‐Asn‐Gln‐Asp sequence was found in κ‐casein (κ‐CN) f107–115 from milk. The inhibitory activity of this nonapeptide (κ‐CN f107–115) was almost preserved even after successive digestion with pepsin, trypsin and chymotrypsin. Furthermore, the inhibitory activity of the purified peptide was completely preserved after heat treatment at 100 °C for 20 min. CONCLUSION: The fermented milk prepared with Lactobacillus helveticus 130B4 contained an ACE inhibitory peptide, κ‐CN 107–115. This fermented milk was expected to have anti‐hypertensive effect after ingestion because the peptide was stable to digestive protease and heat treatment in vitro. Copyright © 2008 Society of Chemical Industry  相似文献   

16.
Nine by‐products used in animal nutrition were examined for their nutritive value by determining the chemical composition (crude protein, crude fat (ether extract), neutral detergent fibre, acid detergent fibre, lignin), in vitro organic matter digestibility and rumen fermentation kinetics (from gas production curves measured in vitro). The by‐products studied were giant pumpkin, red pepper, stem broccoli, brewer's grain, fresh artichoke, scalded artichoke, lemon peel, orange peel and melon. The nutritive value was very variable, depending on the by‐product and on the process applied to the material during industrial processing. In vitro gas production was measured for 500 mg dry matter in quadruplicate at 39 °C after 6, 12, 24, 36, 48 and 72 h of incubation and fitted to single‐pool exponential equations. The fermentation kinetics indicated that brewer's grain was the only by‐product which fitted well with the p = a + b(1 ? e?ct) equation model; all other by‐products had a very fast degradation rate and their gas production fitted the equation p = b(1 ? e?c(t?L)), because in the other exponential model a was negative. © 2002 Society of Chemical Industry  相似文献   

17.
Interactions of mixed cultures [lactic acid bacteria (LAB) and food‐borne pathogens (FBP)] on putrescine (PUT) as well as other biogenic amines (BAs) production were investigated in ornithine‐enriched broth. Significant differences in BAs production were found among the bacterial strains (P < 0.05). Conversion of ornithine into PUT by Salmonella Paratyphi A and Aeromonas hydrophila as well as Listeria monocytogenes and Staphylococcus aureus was high (>75 mg L?1), whereas other bacterial strains yielded below 50 mg L?1 of PUT. LAB strains resulted in significant reduction in PUT by Pseudomonas aeruginosa and Enterobacteriaceae, except for Escherichia coli, which was stimulated more than two‐fold PUT in the presence of Lactococcus lactis subsp. lactis. Lactobacillus plantarum had generally inhibition effect on histamine (HIS) and tyramine production by FBP, whereas Lc. lactic subsp. lactic slightly stimulated HIS by E. coli and A. hydrophila. Streptococcus thermophilus resulted in 1.5‐fold higher HIS formation by bacteria (10 mg L?1). Consequently, the interaction between LAB and specific FBP might result in significant inhibition of amine accumulation, if the correct LAB strains are used.  相似文献   

18.
BACKGROUND: In order to investigate new sources of dietary phytochemicals, recent studies have focused on underexploited seeds. In this study the total lipid contents, fatty acid profiles and levels of soluble proteins, minerals and antioxidants in seeds from 12 Acacia cyanophylla ecotypes commonly grown in Tunisia were determined. RESULTS: Total lipids averaged 101.7 g kg?1 on a dry weight basis. Linoleic (61.11–65.45% of total fatty acid content), oleic (19.67–22.85%) and palmitic (9.18–9.98%) acids were the principal fatty acids. Smaller proportions of stearic (1.49–1.82%), vaccenic (1.13–2.05%) and palmitoleic (0.34–0.58%) acids were also quantified. Proteins (by Kjeldahl assay) averaged 107.2 g kg?1 on a dry weight basis. Total phenolics averaged 1.91 g gallic acid equivalent kg?1 dry weight (DW) and total flavonoids averaged 0.40 g rutin equivalent kg?1 DW. The free radical‐scavenging activity determined by 2,2‐diphenyl‐1‐picrylhydrazyl assay averaged 0.59 mmol L?1 Trolox equivalent antioxidant capacity (TEAC), while that determined by 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) assay averaged 0.28 mmol L?1 TEAC. CONCLUSION: The findings of this study confirm the presence of ω6 fatty acids at high levels in A. cyanophylla seeds. These metabolites could be used as such and/or extracted for the formulation of supplements and/or ingredients to provide a ratio close to the ideal for the ω3/ω6 balance. Copyright © 2012 Society of Chemical Industry  相似文献   

19.
The yeast ecosystem of Nem chua, a Vietnamese traditional fermented sausage naturally rich in medium‐chain‐length lipid‐derived flavouring compounds, was investigated to select biocatalysts able to produce the C10‐fatty acid‐derived aroma compound γ‐decalactone. The total number of yeast was about 5 × 104 to 4 × 105 CFU g?1, and eighty four different species were identified from morphological, physiological and 26S rDNA characteristics, with Candida sake and Candida haemulonii being found in all samples. Six strains able to produce γ‐decalactone from castor oil were selected, of which three Yarrowia lipolytica strains were able to produce between 1 and 2 g L?1 in our study. The strains produced the same amount from the acyl substrate under the form of ester or free fatty acid. Every strain degraded the product at the end of the culture. These high productions make them good candidates for industrial processes and confirm that traditional fermented foods are interesting bioresources for biocatalysts.  相似文献   

20.
Supplementation of milk and oat hydrolysate containing medium with Jerusalem artichoke concentrate (JAC) and subsequent fermentation with probiotic dairy starters resulted in substantial stimulation of probiotics Bifidobacterium lactis and Lactobacillus acidophilus as well as yogurt starter culture Lactobacillus bulgaricus development and acidification rate. The strain-specific responses of the general yogurt cultures, as well as probiotics to the addition of JAC, should be considered to achieve optimal composition of probiotic strains and conformable fermentation conditions. JAC is suggested to be perspective prebiotic additive for fermented synbiotic milks or oat-hydrolysate-based products.  相似文献   

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