Lactic acid bacterial fermentation on the production of functional antioxidant herbal Anoectochilus formosanus Hayata

This study evaluated a novel use of the traditional Asian herb Anoectochilus formosanus. This plant is a traditional food item, generally used for the treatment of liver disorder, hepatitis, hypertension, diabetes, cardiovascular disorder, etc. In this study, the root, stem, and leaf of A. formosanus were used as substrates for lactic fermentation. The fermentation products were analyzed for their total antioxidant activity, reducing power, and scavenging effect on superoxide anion radicals and hydrogen peroxide. The pH of the fermentation medium reached its lowest value, 3.5, at the 35th hour of fermentation. Antioxidant activity of A. formosanus was found to be 61-78%. Lactobacillus longum-led fermentation exhibited the greatest reducing power with an average of 0.3. The products of fermentations utilizing the three plant parts as substrates exhibited a similar scavenging activity (27-30%) on free radicals. This study may suggest a novel use of lactic-fermenting A. formosanus in the production of functional food.     

功能性乳酸菌发酵剂在食品发酵工业中的应用

功能性乳酸茼发酵剂是具有一种或几种固有功能特性的发酵剂，其在感官、技术、营养或健康方面的各种优势使之在食品发酵工业中的应用潜力巨大：它可用于食品防腐、提高食品安全性，改善食品质构和风味，加速奶酪成熟，可产生功能因子、去除毒副因子从而使食品具有保健功效；某些抗噬菌体发酵剂还可解决乳品工业中的噬菌体污染问题。通过基因工程或菌株筛选可以获得所需的功能性发酵剂．它使人们可以更好地控制发酵过程，为消费者提供新型健康食品，此外还有利于食品企业的多样化生产。     

木醋杆菌对乳酸菌发酵复合果汁的影响

本研究探讨了木醋杆菌对复合果汁乳酸菌发酵后乳酸菌活菌数、乳酸菌对胃肠道的耐受性和主要营养成分及抗氧化能力的影响。结果表明,在30℃的条件下,乳酸菌在复合果汁生长迅速,发酵24h后,活菌数均达8.50log cfu/mL以上;单一发酵组与共发酵组经人工胃液、人工肠液消化后乳酸菌存活率均在60.00%以上,通过胆盐、体外消化后存活率均对比MRS肉汤发酵组存活率有所提高;木醋杆菌可增加乳酸菌的胆盐耐受能力。发酵后的复合果汁pH值均下降到3.90以下,葡萄糖、苹果酸和Vc含量均显著性降低(p0.05),乳酸含量和抗氧化活性(ORAC值)均显著性提高(p0.05),木醋杆菌与乳酸菌共发酵显著降低复合果汁中单糖的含量,增加乙酸和纤维素产量(p0.05)。综上所述,木醋杆菌能够在一定程度上提高乳酸菌胃肠道耐受性,降低复合果汁的单糖含量,增加果汁的酸度和细菌纤维素的含量。     

Effect of applying formic acid,heterolactic bacteria or homolactic and heterolactic bacteria on the fermentation of bi‐crops of peas and wheat

This work aimed to compare the effectiveness of bacterial inoculants or a chemical additive for preserving whole‐crop silages made from wheat, two pea varieties (cv Magnus or Setchey) or intercrops of wheat and both pea varieties. The forages were harvested when the wheat and peas were at the late milk and yellow wrinkled stages respectively, and conserved in five replicate mini silos without treatment (control) or after treatment with 2.5 g kg^?1 of formic acid (FA) or 1 × 10⁶ cfu g^?1 fresh forage of either of two bacterial inoculants (WholeCrop Gold (WCG) or WholeCrop Legume (WCL), Biotal Ltd, Cardiff, UK). WCG contained Lactobacillus buchneri, while WCL contained L buchneri, L plantarum and Pediococcus pentosaceus. Chemical composition, fermentation characteristics and in vitro digestibility were measured after 65 days of ensiling. Additive‐treated bi‐crops had lower (P < 0.05) concentrations of soluble N, ammonia N and lactic acid than the controls. Inoculant‐treated bi‐crops had higher (P < 0.001) acetic acid and lower (P < 0.001) residual water‐soluble carbohydrate (WSC) concentrations than FA‐treated bi‐crops. WCL‐treated bi‐crops had similar residual WSC concentrations to and higher (P < 0.05) starch concentrations than WCG‐treated bi‐crops. Unlike Magnus pea bi‐crops, Setchey pea bi‐crops treated with WCL had lower concentrations of ammonia N (P < 0.01) and acetic acid (P < 0.001) and higher concentrations of starch (P < 0.001) and lactic acid (P < 0.05) than those treated with WCG. For both bi‐crops, FA‐treated bi‐crops were more stable (P < 0.05) than inoculant‐treated or untreated silages, and the stability of inoculant‐treated and untreated silages was similar. Formic acid treatment was also the most effective at reducing WSC losses in the bi‐crop and pea silages. Inoculant treatment reduced proteolysis in these forages but did not prevent spoilage in the bi‐crops. Additive treatment reduced yeast counts but did not improve the fermentation in wheat silages. Copyright © 2004 Society of Chemical Industry     

Effects of a mixture of lactic acid bacteria applied as a freeze-dried or fresh culture on the fermentation of alfalfa silage

Alfalfa (approximately 31% DM) was untreated or treated with a silage inoculant containing the lactic acid bacteria Lactobacillus lactis, Lactobacillus plantarum L-54, and L. plantarum Aber F1. The inoculant was added at a normal and a high dose as a freeze-dried powder that had been mixed with water just prior to application, or it was grown with nutrients the day before and added as a fresh culture. The actual application rate of lactic acid bacteria was 1.19 × 10⁵ for the normal dose, 4.30 × 10⁵ for the high dose, and 5.10 × 10⁵ for the fresh culture. All inoculated silages showed a faster increase in the rate of lactic acid production and a decrease in the drop in pH over the first 24 h of ensiling compared with untreated silage. The effect was greatest for silage treated with the fresh culture and was supported by the fact that this treatment had numbers of lactic acid bacteria that increased faster than in other treatments. Inoculation also generally resulted in a fermentation profile that was more homolactic (more lactic acid and less acetic acid, ethanol, and NH₃-N) than for untreated silage, but the effect was greatest for the fresh culture. Inoculation did not affect in vitro neutral detergent fiber digestion or the concentrations of neutral detergent fiber or total N in silages. The recovery of dry matter was greater in silage that was treated with a high level of the freeze-dried culture or with the fresh culture when compared with the untreated control. This study showed that application of a silage inoculant as a freeze-dried culture or as a fresh culture resulted in alfalfa silage with a more homolactic fermentation profile. The effect was greatest from addition of the fresh culture.     

Assessment of a mobile phone for use as a spectroscopic analytical tool for foods and beverages

A mobile phone was used to perform optical analyses of foods and beverages. The phone’s screen served as illumination source and front view camera recorded images. Reflected intensities were used to discriminate between the different samples analysed by principal component analysis. Samples studied illustrated the technique’s potential analytical capabilities with respect to adulteration and authenticity. Three coloured additives (red, green and blue) in the concentration range 2–10 mg L^?1 in a lemon lime beverage were discriminated. Adulteration by up to 25% water of milk with 3% fat content was detected with an estimated detection limit of about 3% water. Changes occurring on a green onion surface over a 48‐h ageing period at room temperature were monitored. Five different cuts from lamb carcasses weighing 9 and 14 kg were classified by the method. Considerable additional work with regard to sampling, data treatment and quantifying results is necessary before the goal of using the technique as a point‐of‐purchase analytical tool can be realised.     

Dissolution tests as a tool for predicting bioaccessibility of nutrients during digestion

Bioaccessibility and bioavailability of active ingredients (like vitamins, antioxidants, etc.) into food systems is often compromised by factors like low permeability and/or solubility within the gut, lack of stability during food processing (temperature and oxygen) as well as in the gastrointestinal tract (pH, enzymes, presence of other nutrients). Moreover, little is known on the influence of food structure and breakdown in the gut on nutrient release. The possibility of predicting the release of nutrients from food matrices under simulated gastrointestinal conditions is of great relevance in order to define which food matrix is best for which nutrient, as well as for looking at the interaction of ingredients with the enzymes involved in the digestive process. This study explores the potential relevance of dissolution tests as a tool for predicting bioaccessibility of nutrients during in vitro digestion. Whey protein hydrogels containing green tea extract (GTE) were chosen for this study. Different simulated in vitro gastrointestinal conditions (GI) were applied throughout the dissolution experiments and the GTE was analysed by UV–vis absorption spectroscopy. It was possible to distinguish between two different release kinetics when experiments were performed in simulated gastric or intestinal media. In the gastric step, the kinetic of GTE release was lower than in an intestinal environment, suggesting that more GTE is released and available for absorption into the intestine than in the stomach. The present study shows that it is possible to use the dissolution tester as a screening method to mimic nutrient release from a food matrix in the gastrointestinal tract.     

The choice of strains of Lactobacillus species for the lactic acid fermentation of vegetable juices

 The reasons for using lactic acid bacteria are to make food durable, to improve its taste and to maintain the nutritive, physiological and hygienic value of the fermentation products. Sixteen strains of the genus Lactobacillus were tested on samples of white fresh cabbage and of a sterilized cabbage and carrot juice mixture. After 7 days of lactic acid fermentation at 27  °C or 30  °C, reducing sugars, total acidity, pH value, lactic, citric and acetic acids, ammonia, nitrates and nitrites were measured in the samples. On the basis of the criteria mentioned above three strains were acceptable. These strains reduced the content of nitrates in the original samples. Received: 14 December 1998 / Revised version: 18 March 1999     

Comparison of nixtamalization and extrusion processes for a reduction in aflatoxin content

Traditional nixtamalization and an extrusion method for making the dough ( masa ) for corn tortillas that requires using lime and hydrogen peroxide were evaluated for the detoxification of aflatoxins. The traditional nixtamalization process reduced levels of aflatoxin B 1 (AFB 1 ) by 94%, aflatoxin M 1 (AFM 1 ) by 90% and aflatoxin B 1 -8,9-dihydrodiol (AFB 1 -dihydrodiol) by 93%. The extrusion process reduced levels of AFB 1 by 46%, AFM 1 by 20% and AFB 1 -dihydrodiol by 53%. Extrusion treatments with 0, 0.3 and 0.5% lime reduced AFB 1 levels by 46, 74 and 85%, respectively. The inactivation of AFB 1 , AFM 1 and AFB 1 -dihydrodiol in the extrusion process using lime together with hydrogen peroxide showed higher elimination of AFB 1 than treatments with lime or hydrogen peroxide alone. The extrusion process with 0.3% lime and 1.5% hydrogen peroxide was the most effective process to detoxify aflatoxins in corn tortillas, but a high level of those reagents negatively affected the taste and aroma of the corn tortilla as compared with tortillas elaborated by the traditional nixtamalization process.     

Lactic acid fermentation improves the quality of amahewu, a traditional South African maize-based porridge

The ability of traditional amahewu fermentation to increase protein digestibility and detoxify mycotoxins commonly contaminating maize in southern Africa was investigated. Commercial maize meal, with or without a range of added ingredients, was fermented, following the traditional way, and the levels of proteins and amino acids assessed. Traditional amahewu samples (and the maize meal used to prepare them) were also collected from a neighbouring rural village. Mycotoxin levels (aflatoxin B₁, fumonisin B₁ and zearalenone) in maize meal and amahewu were analysed and compared in the two sets of samples. Increased levels of protein were observed in amahewu, especially in the samples with added yeast and bread flour (up to 149%), in comparison to the levels in starter maize. In addition, the mycotoxins detected in maize samples were drastically reduced, by 76.5–100%, following fermentation. This observation shows that traditional amahewu fermentation may improve the nutritional quality of maize-based foods and reduce the levels of toxic/carcinogenic mycotoxins.     

透明质酸产生菌分批发酵工艺条件的研究

采用10L小型发酵罐,对变异菌株的分批发酵生产HA的培养条件进行了研究。分别考察了初糖浓度、pH、培养温度、氧的传递、HA合成前体UMP的添加对发酵的影响。结果表明,高的初糖浓度对菌体的生长和HA的合成产生抑制作用,发现5%的初糖浓度比较合适。比较理想的小罐分批发酵条件为:搅拌转速为200r/min、pH7.0、培养温度37℃、通气量2L/min。HA合成前体UMP的添加可以促进菌体的繁殖和大幅度地提高HA的产量。     

Food cooking methods contribute to the reduced vitamin C content of foods prepared in hospitals and care facilities: a systematic review

Recent cases of scurvy within health care have been reported internationally. One potential reason is vitamin C losses associated with food cooking methods. This review systematically synthesised the published literature to determine the extent that vitamin C in food is lost secondary to food cooking methods used in hospitals or care facilities. The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and was prospectively registered in the Prospective Register for Systematic Reviews. Searches were run in three databases with no date restrictions, complemented by an internet search and reference checking. Search terms focused on the intervention and outcome. The final review included seven publications including longitudinal studies and comparison to reference standards. All studies identified vitamin C losses between preparation and service resulting from food cooking methods. Quality was rated as positive for four papers and neutral for the remainder of the included library.     

复合乳酸菌在发芽糙米乳中的发酵特性

将植物乳杆菌、鼠李糖乳杆菌、嗜酸乳杆菌、干酪乳杆菌4种乳酸菌经三三组合后作为复合发酵剂对发芽糙米乳进行发酵,通过分析酸度、活菌数、脱水收缩作用敏感性、蛋白质分解力、流变学性质等实验结果,对各乳酸菌组合的发酵特性进行评价,最终筛选出适合发酵发芽糙米乳的最佳菌株组合。结果表明:植物乳杆菌-嗜酸乳杆菌-干酪乳杆菌组合所得到的发酵发芽糙米乳具有较高的品质。该发酵糙米乳在4℃条件下贮藏21 d后酸化程度较弱,下降了0.71个单位;活菌数变化小且冷藏期间数量一直高于8.7(lg(CFU/m L)),游离氨基酸平均含量达0.86 mmol/L,流变学性质显示其剪切稀化作用较弱。故该乳酸菌组合较为适合发酵发芽糙米乳。     

Selection of lactic acid bacteria for acidification of brown juice (grass juice), with the aim of making a durable substrate for L‐lysine fermentation

BACKGROUND: Brown juice is a waste product from the green crop‐drying industry. Heating and pressing of green crops prior to drying produces a juice rich in nutrients, which can be converted to a stable universal fermentation medium by lowering its pH to 4.0–4.5 via lactic acid fermentation. The aim of this study was to select a strain of lactic acid bacteria for industrial acidification of brown juice. RESULTS: Several strains were tested in fermentation experiments and Lactobacillus salivarius ssp. salivarius DSM 20555 was found to be the best choice. It showed high growth rates at temperatures ranging from 40 to 48 °C, with an optimum temperature of 46 °C (µ_max = 2.2 h^?1), and maintained a high productivity at pH 4.0 in continuous fermentation. The highest productivity of 7.23 g L^?1 h^?1 was found at a dilution rate of 1.0 h^?1. CONCLUSION: With today's increased focus on utilisation of residues from food and agro‐industry, coupled with restrictions on their use as fertiliser for farmlands, lactic acid fermentation could play a significant role in conservation of these nutrient‐rich liquids. This study shows that Lb. salivarius ssp. salivarius DSM 20555 is a very promising micro‐organism for use in such a process. Copyright © 2008 Society of Chemical Industry     

Sourdough fermentation as a tool for the manufacture of low-glycemic index white wheat bread enriched in dietary fibre

Three Lactobacillus strains were selected and used together as sourdough starter. Sourdough performances were evaluated for 30 days. Three breads were manufactured: wheat sourdough bread (WSB), WSB enriched with oat and rye fibres (WSB-DF) and wheat yeasted bread (WYB) fermented with baker’s yeast alone. WSB-DF and WSB showed higher specific volume and lower firmness than WYB. Sensory analysis showed that WSB-DF and WSB were preferred due to acidulous smell, taste and aroma. Compared to WYB and WSB, WSB-DF had high level of dietary fibre (DF). WYB was used as the control to estimate the hydrolysis index (HI = 100). WSB-DF had values of HI lower than WSB (59 vs. 86%). As estimated on 20 volunteers, the value of GI for WSB-DF was ca. 41%. WSB-DF bread manufactured at industrial plant combined low-GI with physiologically significant supply of DF and high standard structure and sensory features.     

低场核磁共振在肉与肉制品水分测定与分析中的应用研究进展

目的：开展预包装即食牛肉保质期快速、准确和无损的预测方法研究,对于保障产品货架期安全具有重要意义。方法：以预包装即食牛肉为分析对象,采集样品低场核磁H质子的T₂弛豫时间,建立即食牛肉水分含量定量分析模型,结合样品感官接受性等建立预包装即食牛肉保质期预测模型。结果：预包装即食牛肉低场核磁谱图横向弛豫时间可较好地反映出随着贮存时间的延长航天即食牛肉的品质变化。建立了即食牛肉含水量预测模型,模型的预测误差小于4%;建模集相关系数（r）为0.9405,校正标准差（RMSECV）为34.5,相对分析误差（RPD）为3.1,对10个分别贮存一定时间但未参与建模的样本分别进行距离货架期终点的预测,预测结果与实测值的的相关性达0.99,预测结果的误差范围为0.7%～9.9%,RMSEP为13.6,预测模型的精确度满足货架期预测的精度要求。结论：低场核磁共振技术在预包装即食牛肉产品保质期预测方面具有应用潜力。

     

Characterisation of vitamin B12 immunoaffinity columns and method development for determination of vitamin B12 in a range of foods,juices and pharmaceutical products using immunoaffinity clean-up and high performance liquid chromatography with UV detection

New rapid and simpler procedures, using immunoaffinity columns, have been developed for the determination of vitamin B12 in a range of samples including three different US National Institute of Standard and Technology (NIST) Reference Materials, infant formula, powdered energy drinks and bars, wheat breakfast cereal, carbonated soft drinks, fruit juices and vitamin B12 tablets. The procedures involved extraction of vitamin B12 using water or sodium acetate buffer and enzyme digestion (using pepsin or α-amylase, or both) if necessary. The extract was clarified and passed through “EASI-EXTRACT® Vitamin B12”, an immunoaffinity column containing monoclonal antibody with high affinity and specificity to vitamin B12. Subsequently, the vitamin B12 immunoaffinity column was washed with 10 ml water and the vitamin B12 was released from the column with 3 ml methanol. Following evaporation, the samples were reconstituted in mobile phase and analysed by HPLC–UV at 361 nm on an ACE 3AQ analytical column using a gradient elution consisting of 0.025% trifluoroacetic acid in water and acetonitrile. Analysis of three types of NIST Standard Reference Materials in triplicate demonstrated the results of the immunoaffinity column method were comparable to microbiological assay results. Method repeatability was determined for all samples analysed and ranged between 0.8 and 10%, demonstrating the method was repeatable with complex matrices (NIST 2383) containing low levels of vitamin B12 (0.44 μg per 100 g), as well as simpler matrices, such as vitamin tablets containing high levels (2000 μg per 0.849 g) of vitamin B12.