Optimisation of a pilot‐scale spray drying process for probiotic yoghurt,using response surface methodology

The influence of drying air temperatures, drying air flow rate and feed flow rate on percentage survival rate (% SR) of starter and probiotic bacteria, moisture content, water activity and colour of probiotic yoghurt powder produced using a pilot‐scale spray dryer was investigated. Optimisation of spray drying conditions was achieved based on the desirability value. Results showed that inlet air temperature, drying air flow rate, feed flow rate and outlet air temperature of 150 °C, 478 m³/h, 2 L/h and 63.3 °C, respectively, were optimal conditions to produce powder that meets quality specifications and with a satisfactory% SR.     

Effects of probiotic yoghurt on symptoms and intestinal microbiota in patients with irritable bowel syndrome

The aim of the present study was to investigate the efficacy of probiotic yoghurt Lactobacillus rhamnosus GG (LGG) in the treatment of Irritable bowel syndrome (IBS). Eighty‐three IBS patients yielded data to be analysed from this 9‐week, placebo‐controlled, double‐blind and randomized trial. The patients consumed either a LGG‐containing probiotic yoghurt (treatment group; n = 44) or a placebo (n = 39) twice daily for 6 weeks. The results indicate that this probiotic yoghurt was effective in alleviating some IBS symptoms and resulted in slight changes in certain gut microbiota. Probiotic yoghurt may represent a treatment for some gastrointestinal disorders.     

Physiochemical,textural, sensory properties and probiotic survivability of Chinese Laosuan Nai (protein‐fortified set yoghurt) using polymerised whey protein as a co‐thickening agent

A new Chinese Laosuan Nai (protein‐fortified set yoghurt) was developed using polymerised whey protein (PWP, 0.4%, w/v) as a co‐thickening agent. The prototype was analysed for physiochemical, textural, sensory properties and probiotic survivability and compared with a commercial sample. Experimental yoghurts were significantly higher in pH, protein content, hardness and viscosity (P < 0.01). Microstructure indicated a uniform and denser protein network. Probiotics remained stable for Bifidobacterium during a 10‐week storage period. Results indicated that polymerised whey protein may be a novel protein‐based co‐thickening agent for making Chinese Laosuan Nai.     

Viability of probiotic micro-organisms during storage, postacidification and sensory analysis of fat-free yogurts with added whey protein concentrate

The aim of this research was to evaluate the effect of the addition of whey protein concentrate (WPC) on the viability of Lactobacillus acidophilus and Bifidobacterium longum and on postacidification throughout the shelf life of fat-free yogurts, and also to analyse the sensory characteristics of the products. Postacidification was not significantly changed by the addition of WPC, but was decreased by Lactobacillus bulgaricus inoculation. WPC did not influence the viability of the lactic acid bacteria ( L. bulgaricus and Streptococcus thermophilus ), but it improved the growth and survival of the micro-organisms L. acidophilus and B. longum , especially the former. The panellists did not identify significant differences ( P <  0.05) of the yogurts due to the addition of WPC.     

Comparison of kinetic profile of free and immobilized glucose oxidase, immobilized on low-density polyethylene using UV polymerization

ABSTRACT:  Bioactive packaging is an important area of active packaging in which an active component is incorporated into the food contact surface of the package to interact with the food components without itself migrating into the food. Embedding bioactivity in a UV polymerizable resin is a novel and versatile technique for incorporating bioactive components into food packaging. In a previous article, glucose oxidase was immobilized in a packaging material using a UV curable resin. The relevance of this model system for deoxygenation of fruit juices was discussed. Though the technique efficiently immobilized enzymes in packaging material, during polymerization and immobilization the catalytic ability of the enzyme was not specifically explored. This article compares and contrasts the catalytic ability in terms of the kinetic profile of free and immobilized enzyme for the same model system: deoxygenation of juices. Kinetic behavior of immobilized and free glucose oxidase enzyme was evaluated at both shelf stable (room temperature) and refrigerated storage conditions to simulate the actual package life. It was observed that both the free enzyme and the immobilized enzymes follow the Michaelis–Menten kinetics model. There was no significant difference between the catalytic ability ( k_cat / K_m ) of free and immobilized enzymes at treatment temperatures (30, 25, and 10 °C); however, at refrigeration temperature (5 °C), the values for free enzyme were significantly higher than the immobilized enzyme.     

Comparative analysis of physicochemical,rheological, sensory and flavour properties of yoghurts using a new probiotic Bacillus coagulans 13002 with traditional yoghurt starter

Bacillus coagulans 13002 (13002) as a new potential starter was incorporated into the yoghurts for fermentation in this study. We compared three groups of yoghurt, including Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (SL), 13002 (BCS), and 13002 and SL (BCS + SL). Compared with the combination of SL and BCS, the group of BCS + SL exhibited better flavour, higher titratable acidity, cohesiveness and richer volatile compounds, suggesting that the combination of BCS and SL was more efficient to produce the best sensory properties of yoghurt (P < 0.05). The production of volatile compounds in fermentation with and without the addition of BCS was mainly affected by aldehydes, ketones, esters and hydrocarbons, respectively. Furthermore, BCS additions into traditional starters resulted in increasing organic acids and speeding up the usage of sucrose and lactose during the fermentation period of yoghurt. Our study suggested that BCS is a favourable starter supplement for improving the quality of probiotic yoghurts.     

Comparison of adaptive neuro‐fuzzy inference system and artificial neural networks for estimation of oxidation parameters of sunflower oil added with some natural byproduct extracts

BACKROUND: Apple pomace, orange peel and potato peel, which have important antioxidative compounds in their structures, are byproducts obtained from fruit or vegetable processing. Use of vegetable extracts is popular and a common technique in the preservation of vegetable oils. Utilization of apple pomace, orange peel and potato peel extracts as natural antioxidant agents in refined sunflower oil during storage in order to reduce or retard oxidation was investigated. All byproduct extracts were added at 3000 ppm to sunflower oil and different nonlinear models were constructed for the estimation of oxidation parameters. RESULTS: Peroxide values of sunflower oil samples containing different natural extracts were found to be lower compared to control sample. Adaptive neuro‐fuzzy inference system (ANFIS) and artificial neural networks (ANN) were used for the construction of models that could predict the oxidation parameters and were compared to multiple linear regression (MLR) for the determination of the best model with high accuracy. It was shown that the ANFIS model with high coefficient of determination (R² = 0.999) performed better compared to ANN (R² = 0.899) and MLR (R² = 0.636) for the prediction of oxidation parameters CONCLUSION: Incorporation of different natural byproduct extracts into sunflower oil provided an important retardation in oxidation during storage. Effective predictive models were constructed for the estimation of oxidation parameters using ANFIS and ANN modeling techniques. These models can be used to predict oxidative parameter values. Copyright © 2011 Society of Chemical Industry     

Estimation of oxygen uptake rate of tomato (Lycopersicon esculentum Mill.) fruits by artificial neural networks modelled using near-infrared spectral absorbance and fruit mass

The oxygen uptake rate of tomato fruits was estimated by an artificial neural network (ANN) model using near-infrared (NIR) spectral absorbance and fruit mass. The absorption peak apex from cytochrome c oxidase (COX) was confirmed at 841 nm for mitochondrial preparation and at 833 nm for intact fruits. The results of a proteome analysis that detected the putative COX subunit II PS17 from the mitochondrial preparation biochemically supported the presence of the absorption peak due to COX. An ANN model for estimating O₂ uptake rate was developed from the absorbance data at 11 wavelengths from 645 to 979 nm including 833 nm and fruit mass as input variables. The O₂ uptake rate was estimated by the proposed model with a correlation coefficient of 0.79 and a standard error of prediction of 0.091 mmol kg⁻¹ h⁻¹. This method may be effective for rapid estimation of shelf life and physiological activity of tomato fruits.