Hedonic perception and preference analysis of double cream cheeses formulated with raw and pasteurized milk

Objective: To compare the characteristics of double cream cheeses made with raw and pasteurized milk per liking and preference level. Design/Methodology/Approach: Cheeses from three brands were evaluated: Santa Teresa, Montero, and Colegio de Postgraduados (CP). The first two cheeses were formulated with raw milk, while the CP cheese was formulated with pasteurized milk inoculated with lactic cultures. The hedonic perception study was carried out in monadic series with 19 volunteers who blind tasted the three types of cheese. The evaluation attributes were: appearance, taste, aroma, and general acceptability on a 9-point scale; and saltiness, acidity, and creaminess on a 3-point scale (JAR). Preferences were evaluated by rank and multiple comparison tests. Results: No differences were found in the aroma, taste, and texture liking level of the cheeses (p>0.05); nevertheless, there were differences in the appearance and general acceptance (p˂0.05). The general acceptance of the CP cheese was significantly lower than that of the two raw milk cheeses (p˂0.05). The penalty analysis showed that low acidity and low creaminess attributes are related to a low general acceptance (p˂0.05). Limitations/Implications: The study has enough evaluations for statistical tests. Findings/Conclusions: Raw milk cheeses obtained the highest marks in all attributes. Determining if there are other sensory attributes —in addition to those that were the subject of this study— will help to explain the greater preference and global acceptance of raw milk cheeses

Evaluation of fermentative activity of lactic cultures for dehydrated yogurt with the use of different additives

Objective: To evaluate the fermentative activity of dehydrated lactic cultures with the use of various additives and vacuum drying, using yogurt as a model system. Design/methodology/approach: The yogurt was made with commercial lactic cultures (YF-L705 Yo-Flex CHR HANSEN) inoculated in whole milk incubated for 4 h/42°C. The yogurt was centrifuged at 6,000 rpm/15 min/4°C. The supernatant was removed, and the following additives were added to the precipitate: 1) SN, without additives, 2) Glycerol, 3) Calcium carbonate, 4) Yeast extract, 5) Glycerol and calcium carbonate, 6) Glycerol, calcium carbonate and yeast extract. The drying of 6 treatments was done up to 96h inside vacuum desiccators. Weight and moisture loss were recorded at 0, 24, 48, 72 and 96h. The dehydrated portions with the additives 1,2,3,4,5,6 was used as inoculums in milk for the production of yogurt; recording the drop in pH up to 24h and FTIR. As a control, non-dehydrated and lyophilized portion of yogurt were used. Results: The drying time at constant weight was 3 days. Dehydrated cultures containing yeast extract and calcium carbonate are associated with faster milk fermentation activity (p ≤ 0.05). Yoghurts manufactured with fresh cultures take 4 hours to ferment, dehydrated ones take over 12 hours. Infrared spectra show that yogurts produced with fresh or dried strains are of similar qualities. Study limitations/implications: The fermentative activity in dehydrated foods improves when alkalis are added, such as calcium carbonate, which is an antacid and releases CO2 upon contact with water and acid, stimulating anaerobiosis. Infrared spectra show that yogurts produced with fresh or dried strains are of similar qualities. Findings/conclusions: The best model to present the fermentation pH change curve is a Boltzman sigmoidal function. Yogurts with fresh or dried cultures differed in the time at which the milk is fermented. The fermentative activity in dehydrated foods improves when alkalis are added, such as calcium carbonate, which is an antacid and releases CO2 on contact with water, stimulating anaerobiosis. Infrared spectra show that yogurts produced with fresh or dried strains are of similar qualities.Objective: To evaluate the fermentative activity of dehydrated lactic cultures with the use of different additives and vacuum desiccation, using yogurt as model system. Design/methodology/approach: The yogurt was elaborated with commercial lactic cultures (YF-L705 Yo-Flex CHR HANSEN) and whole milk incubated at 42 °C for 4 h. Yogurt was centrifuged at 6,000 rpm/15 min/4 °C. The supernatant was eliminated and with the precipitate, 6 treatments were established by addition of additives: T1, Without additive, T2, Glycerol, T3, Calcium carbonate, T4, Yeast extract, T5, Glycerol, and T6, Glycerol, Calcium carbonate and Yeast extract; non-dehydrated and freeze-dried yogurt was used as control: T7 and T8, respectively. The precipitate of the treatments with additives was dehydrated in a silica gel in a desiccator and under vacuum conditions. The weight loss was recorded at 0, 24, 48, 72 and 96 h. The precipitate with dehydrated additives was used as milk inoculates for yogurt elaboration. The change of pH was recorded at 0, 1, 2, 3, 4, 5, 6, 7, 8 and 24 h. With the pH and the fermentation time, a model was established to present the change curve in fermentation pH and the Fourier transform infrared spectroscopy (FTIR). Results: The drying time to constant weight was 3 days. The fermentation pH change curve was a Boltzman sigmoidal function and analysis of variance was conducted with its parameters to assess the different fermentation speeds of the different treatments. The dehydrated cultures with Yeast Extract and Calcium Carbonate are associated with a higher fermentation activity of the milk (p < 0.05). The yogurts manufactured with fresh cultures take 4 to 5 h to ferment and the dehydrated ones take more than 10 h. The infrared spectra showed that the quality of the yogurts produced with fresh or dry cultures are similar, which agrees with other studies. Limitations on study/implications: The dehydrated inoculated with the additives can be used to make yogurt with similar quality as to when inoculate with fresh culture is used, with the disadvantage of the fermentation time being longer. It is possible that this methodology can be used to dehydrate other inoculates based on lactic bacteria, but their effectiveness would have to be assessed experimentally. Findings/conclusions: This study shows an alternative method to dehydrate lactic bacteria in the laboratory with equipment of relatively easy access for any laborator

Kinetics of Lactobacillus plantarum 44a in the faeces of tilapia (Oreochromis niloticus) after its intake in feed

Aims: To study the kinetic passage of Lactobacillus plantarum 44a from feed to faeces of tilapia in order to calculate the number of Lactobacillus excreted. Methods and Results: In a single-dose experiment, duplicate lots of 26 fish devoid of intestinal lactobacilli were fed with diets containing c. 4·5 × 1011, 6·3 × 108, 6·0 × 105 and 0 CFU of Lact. plantarum 44a per single feed ration. In the multiple-dose experiment, duplicate lots of 30 fish each were supplied with a diet containing 1 × l011 CFU of Lact. plantarum 44a as follows: 14 times in 14 days, five times in 14 days, once in 14 days and zero times in 14 days. Faeces were periodically collected and analysed for their lactobacilli content by using a selective media. The kinetics of Lactobacillus in the faeces was described as a pulse signal defined by three parameters: ¿, Ao and the time. ¿, was identified as the time to reach the peak (x axis) and Ao was a constant. Ao divided by e, was identified as the height of the peak (y axis). The area below the curve Ao¿ allowed the calculation of the total number of lactobacilli excreted. The ability of the mathematical model to describe the actual values was tested by a linear regression analysis. In most of the cases, the equations showed an intercept close to zero (P > 0·05) and angular coefficients near one. Conclusions: Lactobacillus plantarum 44a was excreted in short pulse signals described by a mathematical model which allowed calculating the area below the curve and consequently the survival rate. Significance and Impact of the Study: This study provides a quantitative method to study the kinetics of excretion of a probiotic bacterium in the faeces

Presence of lactobacilli in the intestinal content of freshwater fish from a river and from a farm with a recirculation system

Lactobacilli are Gram-positive and catalase negative rods commonly found in lactic acid fermented foods and in the gastrointestinal tract of mammals and birds. Few studies have described lactobacilli in freshwater fish. We analysed the presence of lactobacilli in the intestines of young and adult freshwater fish inhabiting a river environment and from fish reared in an aquaculture unit with a water recirculation system. Various species of lactobacilli were present in relatively high number in the intestines of edible fresh water fish from the river, especially in the warm season but in low numbers in the cold season. Lactobacilli were scarcely found in the intestines of edible farmed fish reared in a recirculation system in warm water. Lactobacilli are reported for the first time from the intestines of wild European eel, perch, rudd, ruffe, bleak, silver bream, chub, somnul and farmed African catfish. The two first fishes, and the last one are highly valuable species for fisheries and aquaculture. Additionally, improved methods for storage and bacteriological analysis of fish intestinal content are described. The natural presence of lactic acid bacteria in fish may be of great interest in producing fermented fish products worldwid

Survival of Lactobacillus plantarum 44a after spraying and drying in feed and during exposure to gastrointestinal tract fluids in vitro

A good probiotic strain should be able to survive the conditions of handling and storage to be delivered in high concentration to the host. That is especially important when stressful conditions are prevalent in the carrier, for instance in low water content foods like animal feed. The aim of this research was to study the survival of the probiotic candidate Lactobacillus plantarum 44a after spraying and drying in feed, and during storage and exposure to gastrointestinal tract fluids in vitro. In addition, the viability of the strain during exposure to distilled water and 2% NaCl was studied. Feed was sprayed with a suspension of ¿2 × 1010 CFU of L. plantarum 44a in 10, 15, 20, 25 and 30% v/w of the feed and dried to constant weight (6% moisture) in a convective oven at 25°C. L. plantarum 44a survived 14.67, 36, 51.86, 78.9 and 105.3% respectively in relation to the original % v/w of the feed. After 3 weeks of storage at 25°C, survival was similarly low in all the treatments. L. plantarum 44a stored in feed containing 13% moisture, vacuum-packaged and stored in refrigeration, maintained high viability (¿100%) after 1 year of storage. Survival was not affected after feed-containing lactobacilli was exposed to gastrointestinal fluids in a simulation model. Viability of L. plantarum 44a as a cell suspension in PBS added directly to distilled water or distilled water with 2% NaCl was maintained up to 48 h; after 72 h, viability started to decline. It is concluded that L. plantarum 44a maintained high viability after being dried and stored in feed even after exposure to gastric and intestinal fluids in vitro

Cassava-based (Manihot esculenta Crantz) fermented energy-protein food for bovines

Cassava (Manihot esculenta Crantz) is a tuber that is used for human consumption and in the diet of animals, it is characterized by having a high starch content and low protein content. In this sense, it is proposed to use solid state fermentation (FES) to obtain a fermented feed based on cassava with a high energy-protein value for cattle. The objective of this work was to evaluate the effect of the levels of yeast inoculum (IL) and days of fermentation, in the chemical, fermentative and microbiological composition of fermented foods based on cassava. A completely randomized design was used with factorial arrangement, 3 levels of yeast inoculum (0, 5 and 10%) and 5 days of fermentation (0, 1, 2, 3 and 4 days). Interaction was found between the factors studied in the variables pH and crude protein (CP). The highest pH values ??were obtained with the addition of 10% of the IL (8.67) and values ??of 16.55% of PC were found. In relation to true protein (PV) and in situ degradation of dry matter (DIMS), no differences were found in the inoculum level or the days of fermentation studied, the PV values ??were 8% and DIMS 80 %. The yeast inoculum and the days of fermentation did not increase the true protein of the fermented cassava-based food.L Objective: To assess the effect of different yeast levels and fermentation times on the chemical, fermentative, and microbiological composition of cassava in order to produce a cassava-based fermented food. Design/Methodology/Approach: We used a completely randomized design with a factorial arrangement, three yeast inoculum levels (0, 5, and 10%), and five fermentation times (0, 1, 2, 3, and 4 days). Results: We found significant interaction of the studied factors with the pH and crude protein (CP) variables. The highest pH values were obtained adding 10% yeast inoculum (YI) (8.67). CP values of 16.55% were found. No differences caused by the studied inoculum levels and fermentation times were found in true protein (TP) and the in situ degradation of dry matter (IDDM). TP and IDDM had 8% and 80% values, respectively. Study Limitations/Implications: A behavior test with bovines must be conducted to demonstrate the potential of cassava-based fermented foods in meat and/or milk production. Findings/Conclusions: The yeast inoculum and the fermentation days did not increase the TP in the cassava-based fermented food

Esterification Optimization of Crude African Palm Olein Using Response Surface Methodology and Heterogeneous Acid Catalysis

In this work, the effect of zeolite montmorillonite KSF in the esterification of free fatty acids (FFAs) of crude African palm olein (Eleaias guinnesis Jacq) was studied. To optimize the esterification of FFAs of the crude African palm olein (CAPO), the response surface methodology (RSM) that was based on a central composite rotatable design (CCRD) was used. The effects of three parameters were investigated: (a) catalyst loading (2.6–9.4 wt %), (b) reaction temperature (133.2–166.2 °C), and (c) reaction time (0.32–3.68 h). The Analysis of variance (ANOVA) indicated that linear terms of catalyst loading (X1), reaction temperature (X2), the quadratic term of catalyst loading ( X 1 2 ), temperature reaction ( X 2 2 ), reaction time ( X 3 2 ), the interaction catalyst loading with reaction time ( X 1 * X3), and the interaction reaction temperature with reaction time ( X 2 * X3) have a significant effect (p < 0.05 with a 95% confidence level) on Fatty Methyl Ester (FAME) yield. The result indicated that the optimum reaction conditions to esterification of FFAs were: catalyst loading 9.4 wt %, reaction temperature 155.5 °C, and 3.3 h for reaction time, respectively. Under these conditions, the numerical estimation of FAME yield was 91.81 wt %. This result was experimentally validated obtaining a difference of 1.7% FAME yield, with respect to simulated values