Lactic acid production from dining‐hall food waste by Lactobacillus plantarum using response surface methodology

BACKGROUND: Food waste generally has a high starch content and is rich in nutritional compounds, including lipids and proteins. It therefore represents a potential renewable resource. In this study, dining‐hall food waste was used as a substrate for lactic acid production, and response surface methodology was employed to optimise the fermentation conditions. RESULTS: Lactic acid biosynthesis was significantly affected by the interaction of protease and temperature. Protease, temperature and CaCO₃ had significant linear effects on lactic acid production, while α‐amylase and yeast extract had insignificant effects. The optimal conditions were found to be an α‐amylase activity of 13.86 U g^?1 dried food waste, a protease activity of 2.12 U g^?1 dried food waste, a temperature of 29.31 °C and a CaCO₃ concentration of 62.67 g L^?1, which resulted in a maximum lactic acid concentration of 98.51 g L^?1 (88.75% yield). An increase in inoculum size would be appropriate for accelerating the depletion of initial soluble carbohydrate to enhance the efficiency of α‐amylase in dining‐hall food waste fermentation. CONCLUSION: A suitable regression model for lactic acid production was developed based on the experimental results. Dining‐hall food waste was found to be a good substrate for lactic acid fermentation with high product yield and without nutrient supplementation. Copyright © 2008 Society of Chemical Industry     

植物乳杆菌在不同基质中转化生成共轭亚油酸的研究

将具有转化亚油酸能力的植物乳杆菌ZS2058分别接入脱脂奶、豆奶和番茄汁中,分别考察了亚油酸的添加量、亚油酸的添加方式和预培养对植物乳杆菌生长和转化亚油酸的能力的影响.结果表明,在脱脂奶中植物乳杆菌转化能力最强,在脱脂奶中该菌能将1 mg/mL亚油酸转化成152.05μg/mL共轭亚油酸.     

Brewing of glucuronic acid-enriched apple cider with enhanced antioxidant activities through the co-fermentation of yeast (Saccharomyces cerevisiae and Pichia kudriavzevii) and bacteria (Lactobacillus plantarum)

Co-fermentation using yeast (Saccharomyces cerevisiae and Pichia kudriavzevii) and the bacteria (Lactobacillus plantarum) as starters isolated from spontaneous sourdough was conducted for the brewing of glucuronic acid (GlcA)-enriched apple cider. The concentration of GlcA in the apple cider co-fermented for 14 d with commercial S. cerevisiae and L. plantarum was 37.7 ± 1.7 mg/mL while a concentration of 62.8 ± 3.1 mg/mL was recorded for fermentation with P. kudriavzevii and L. plantarum, which was higher than the corresponding single yeast fermentation. The co-fermented apple cider revealed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 171.67 ± 0.79 µg trolox equivalents (TE)/mL using P. kudriavzevii and L. plantarum, compared to the control (143.89 ± 7.07 µg TE/mL) just using S. cerevisiae. Thus, the co-fermentation of S. cerevisiae and L. plantarum and P. kudriavzevii and L. plantarum provided a new strategy for the development of GlcA-enriched apple cider with enhanced antioxidant capacity.     

Direct Application of Rep‐PCR on Type I Sourdough Matrix to Monitor the Dominance and Persistence of a Lactobacillus plantarum Starter Throughout Back‐Slopping

This study describes the optimization and application of repetitive element‐PCR (rep‐PCR) technique directly on microbial DNA extracted from type I sourdoughs for fast monitoring of a Lb. plantarum starter strain (P1FMC) throughout daily back‐slopping. The challenge was to follow and study the performance of a starter culture directly in sourdoughs without cultivation on selective media. The extraction of good quality microbial DNA suitable for amplification from a complex matrix such as dough was the first target. In addition, the objective to obtain a clear rep‐PCR profile referable to a specific starter strain among a microbial community was pursued. Co‐inoculum trials, in flour matrix, with Lb. plantarum P1FMC and L. lactis LC71 strains and, subsequently, type I sourdough back‐slopping trials were performed. The rep‐PCR amplification profiles obtained were clearly referable to that of Lb. plantarum P1FMC starter in both co‐inoculum trials (also when it was present with one order of magnitude less with respect to L. lactis LC71) and back‐slopping trials where it dominated the fermentation process with loads of 10⁸ cfu g^?1 and prevailed on the autochthonous microbiota. Thus, the approach proposed in this paper could be considered a methodological advancement, based on a culture‐independent one‐step rep‐PCR, suitable for fast monitoring of starter performance.     

Spray drying conditions for orange juice incorporated with lactic acid bacteria

This work aimed to develop an orange juice powder by spray drying with lactic acid bacteria (Lactobacillus plantarum 299v and Pediococcus acidilactici HA‐6111‐2), testing their survival both during drying and storage (room temperature and 4 °C). Initially, the best conditions for spray drying were chosen to allow the best survival of each LAB: (i) inlet air temperature of 120 °C and (ii) 0.5:2 ratio of the orange juice soluble solids and drying agent added (prebiotics: 10 DE maltodextrin or gum Arabic). Survival of LAB was not affected by drying process, and it was higher when cultures were stored at 4 °C. A slightly higher protection was conferred by 10 DE maltodextrin, in the case of L. plantarum and at 4 °C. Pediococcus acidilactici was more resistant during storage at 4 °C, with logarithmic reductions lower than 1 log‐unit. It was demonstrated that it is possible to produce a functional nondairy product, orange juice powder supplemented with prebiotic compounds, containing viable LAB for at least 7 months, when stored at 4 °C.     

Stability of microencapsulated lactic acid bacteria under acidic and bile juice conditions

The probiotic strains Lactobacillus brevis CCMA1284 and Lactobacillus plantarum CCMA0359 were microencapsulated by spray drying using different matrices – whey powder (W), whey powder with inulin (WI) and whey powder with maltodextrin (WM). Viability of the microencapsulated strains in acid and bile juices and during 90 days of storage (seven and 25 °C) was evaluated. The two strains exhibited high encapsulation efficiency (> 86%) by spray drying. The different matrices maintained L. plantarum viability above six log CFU g⁻¹ at 7 °C for 90 days, whereas similar results for L. brevis were observed only for W. The use of inulin as matrix of encapsulation did not enhance bacterial viability in the evaluated conditions. In general, the use of W and WM as matrices was effective for L. plantarum viability. However, only W was effective for L. brevis in the evaluated conditions. The spray drying technique was successfully adopted for the encapsulation of L. plantarum CCMA0359 and L. brevis CCMA1284 strains.     

Fermentation by Amylolytic Lactic Acid Bacteria and Consequences for Starch Digestibility of Plantain, Breadfruit, and Sweet Potato Flours

The potential of tropical starchy plants such as plantain (Musa paradisiaca), breadfruit (Artocarpus communis), and sweet potato (Ipomoea batatas) for the development of new fermented foods was investigated by exploiting the capacity of some lactic acid bacteria to hydrolyze starch. The amylolytic lactic acid bacteria (ALAB) Lactobacillus plantarum A6 and Lactobacillus fermentum Ogi E1 were able to change the consistency of thick sticky gelatinized slurries of these starchy fruits and tubers into semiliquid to liquid products. Consequently, a decrease in apparent viscosity and an increase in Bostwick flow were observed. These changes and the production of maltooligosaccharides confirmed starch hydrolysis. Sucrose in sweet potato was not fermented by strain A6 and poorly fermented by strain Ogi E1, suggesting possible inhibition of sucrose fermentation. In all 3 starchy plants, rapidly digestible starch (RDS) was higher than slowly digestible starch (SDS) and resistant starch (RS) represented between 17% and 30% dry matter (DM). The digestibility of plantain was not affected by fermentation, whereas the RDS content of breadfruit and sweet potato decreased and the RS content increased after fermentation. Practical Application: The characteristics resulting from different combinations of gluten free starchy plants (plantain, breadfruit, sweet potato) and amylolytic lactic acid bacteria (ALAB) offer opportunities to develop new functional fermented beverages, mainly for breadfruit and sweet potato, after further investigation of their formulation, sensory attributes, nutritional, and prebiotic characteristics.