Revista de microbiología industrial y alimentaria

This study aimed to describe the microbial populations involved in the production of traditional raw milk, semi-dry cheese from Honduras, Central America, particularly the indigenous lactic acid bacteria (LAB) responsible for the organoleptic characteristics of this product. A total of 48 cheese samples were collected from seven of the 18 country’s Departments. Phenotypic methods were used to count, identify and compare the composition of bacteria and yeasts populations in the samples. Twenty LAB isolates were randomly selected to analyse its 16S-23S rRNA spacer region. This method was also applied to understand the diversity of bacterial communities present in the samples. LAB colonies reached average counts of 4.79 lg CFU g-1. Twelve LAB species were identified based on a conventional phenotypic approach. Lactococcus lactis and Enterococcus faecium were the most frequently identified species according to microbiological and molecular methods. No significant correlation was observed among LAB species and geographical distribution. Four genera and five species were identified among the isolated yeasts. This is the first report describing the indigenous biota of traditional raw milk cheeses from Honduras. Our results may provide useful information for valuable strain selection as starter cultures for the industrialization of traditional dairy products in Honduras.

Introduction: Millets are good sources of energy, protein, fatty acids, vitamins, minerals, dietary fibre and polyphenols. Millet bran is therefore a by-product of millet-based food manufacturing. Background: The chemical treatments will decrease the content of anti-nutrients and increase the content of compounds that improve bioavailability. Objectives: The present study with the objectives to study the different method of chemical treatment in barnyard millet bran, and the treated bran and raw bran was analysed for the antinutrional and proximate composition. Materials and Methods: Various pre-treatment done by chemical treatments in Barnyard millet bran, antinutritional and chemical composition and texture analysis were analysed using standard techniques. Results and Conclusion: The various chemical treated bran the calcium hydroxide and hot water treated [treatment-2] barnyard millet bran get decrease the antinutrient factors such as trypsin inhibitor, lipase activity, phytates etc., when compare to raw barnyard millet bran. From the chemical analysis the dietary fibre, protein, ash content was stabilized in [treatment-2] treated bran when compare to other treated bran. The sensorial attributes of rusk at ratio (85:15) and muffin at ratio (75:25) with BMB substitution got highly accept by panel members. Even though BMB slightly increased the hardness of rusk and in muffin increase the strength of muffin.

The production of Allium sativum (AS) cheddar cheese in the presence and absence of fish collagen (FC) compared to plain cheese with/without FC was conducted to determine sensory evaluations during 0, 14, 30, and 60 days of ripening. The evaluation system consists of seven parts; outer appearance, colour, texture, consistency of body, consistency of colour, flavour and aroma. Ripened cheeses were assessed by a sensory panels based on a 10-point system. The present results demonstrated that outer appearance of AS cheese in presence of FC showed the lowest score (2.8 ± 0.09) after 8 weeks of ripening. The color criteria of all fresh cheese samples reduced significantly (p<0.05) at the end of ripening period. The highest flavor score of cheese samples was shown at week 2 of ripening for all cheese samples except of AS-cheese. AS-cheese in the presence and absence of FC registered lower aroma score than their respective control during the period of ripening. In conclusion, AS- and AS+FC-cheeses can be consumed within 2 to 4 weeks of storage for the best organoleptic properties.

The peach-soy toffee was prepared from different blends of peach pulp and soy-slurry. The peach pulp and soybean slurry were blended in the ratios of 100:0, 95:5, 90:10, 85:15, 80:20, 75:25 and 70:30. The product was prepared as per the standard recipes and was stored for four months to ascertain changes in physico-chemical and sensory characteristics. The analysis of toffees revealed significant differences among different blends. In toffees, maximum moisture content of 17.17 per cent was recorded in B1 (100:0:: P:S). The highest TSS and titratable acidity of 12.23 0B and 1.62 per cent were recorded in B1 (100:0:: P:S), respectively. Reducing sugar (37.95 per cent) and total sugar (64.93 per cent) were also found to be highest in B1 (100:0:: P:S). It was observed that protein and fat contents of 3.43 and 8.66 per cent were recorded highest in B7 (70:30:: P:S), respectively, whereas highest ascorbic acid content of 21.80 mg/100 g was recorded in B7 (70:30:: P:S). Sensory evaluation of toffees revealed that the highest score of 8.30 was recorded in B4 (85:15:: P:S) and lowest score of 6.01 was recorded in B7 (70:30:: P:S). In general there was an increase in TSS, acidity and sugars and decrease in protein, fat and ascorbic acid contents and all sensory attributes during four months storage in different blends of toffees.

Pectin lyase finds applications in the degumming and retting of plant fibers where it degrades highly methylesterified pectin without prior action of any other pectinase. Response surface methodology (RSM) has been frequently utilized for the optimization of production process of industrially important enzymes from microbes. In the present work, fermentation conditions for the production of pectin lyase from Bacillus cereus were optimized using the factorial and central composite design of RSM. The cubic order polynomial regression model was found to be adequate and significant with a determination coefficient R2 of 0.9505 (p<0.0001). The ANOVA analysis and three dimensional surface plots confirmed interaction among variables. The optimum values of variables were found to be pectin 4% (w/v), sodium carbonate 1% (w/v), manganese sulfate 0.055% (w/v) and magnesium sulfate 0.018% (w/v) at 150 rpm under response surface curves. After optimization, the experimental value of maximum activity of enzyme (3.37 U/ml) was found higher but close to the predicted value (2.68 U/ml) and the enzyme activity increased by 1.32 fold (32.16%).

Effects of edible coating containing pomegranate peel extract (PPE) on the quality and shelf life of silver carp fillet during refrigerated storage were investigated. Freshly fish fillet were assigned to three treatments: control (fillet treated with edible coating and no antioxidants); fillet treated with edible coating and 5% PPE (T1) and fillet treated with edible coating and 10% PPE (T2). Chemical (pH, peroxide value and thiobarbituric acid) and microbiological (total viable count and psychrotrophic count) analysis were used to evaluated the effect of this treatments during refrigerated storage. The results show that addition of PPE considerably delayed lipid oxidation in silver carp fish fillet in T1 and T2 compared control samples. According to microbiological assay, T1 and T2 samples at days 12 reached to maximum acceptability limit while it was happened in day 9 for control samples. There were significant differences (P<0.05) between treated and control samples at all the days during the refrigerated storage.

The paper proposes a structural model of the solar dryer comprising a closed housing having a rectangular cross section, mounted inside it on the traction chain conveyor mesh trays for a product, drive, fan, electric heater and an annular heat regenerator. The body is covered with a translucent shell of sheet organic glass with a certain gap and forms a loop recirculation of air in the doorway between the cameras mounted additional regenerator shell and tube filled with heat storage material. Gelio drying systems equipped with butterfly valves, pipes and air ducts providing capture solar radiation and heat recovery junk coolant.