Search results

This paper aims to investigate the anti-biocorrosion performance and mechanism of the Cu-bearing carbon steel in the environment containing sulfate-reducing bacterial (SRB).

The biocorrosion behavior of specimens with Cu concentration of 0 Wt.%, 0.1 Wt.%, 0.3 Wt.% and 0.6 Wt.% were investigated by immersion test in SRB solution. By examining the prepared cross-section of the biofilm using focused ion beam microscopy, SRB distribution, bacterial morphology, biofilm structure and composition were determined. The ion selectivity of the biofilm was also obtained by membrane potential measurement. Moreover, the anti-biocorrosion performance of the Cu-bearing carbon steel pipeline was tested in a shale gas field in Chongqing, China.

Both the results of the laboratory test and shale gas field test indicate that Cu-bearing carbon steel possesses obvious resistance to microbiologically influenced corrosion (MIC). The SRB, corrosion rate and pitting depth decreased dramatically with Cu concentration in the substrate. The local acidification caused by hydrolyze of ferric ion coming from SRB metabolism and furtherly aggravated by anion selectivity biofilm promoted the pitting corrosion. Anti-biocorrosion of Cu-bearing carbon steel was attributed to the accumulation of Cu compounds in the biofilm and the weaker anion selectivity of the biofilm. This research results provide an approach to the development of economical antibacterial metallic material.

MIC occurs extensively and has become one of the most frequent reasons for corrosion-induced failure in the oil and gas industry. In this study, Cu-bearing carbon steel was obtained by Cu addition in carbon steel and possessed excellent anti-biocorrosion property both in the laboratory and shale gas field. This study provides an approach to the development of an economical antibacterial carbon steel pipeline to resist MIC.

Wheat is the staple food in many parts of the world and bread is one of the most important products of wheat flour. There is a need for innovations in bread making to increase its shelf life and consumer's attraction. Fermentation is mostly done by yeast but it does not produce appreciable amounts of organic acids, which are required to enhance the shelf life of bread. The present study aims to determine the effect of bacterial and yeast culture blends on the quality and shelf life of sourdough bread and to observe the sugar utilization during fermentation.

Three treatments were made using different blends of bacterial cultures (homo‐fermentative and hetero‐fermentative) and baker's yeast compared with a control having only baker's yeast. Chemical analysis, sugar utilization (Sucrose, glucose and fructose) through high performance liquid chromatography, sensory characteristics (both internal and external) and microbial count (Bacterial and fungal count) for each treatment were conducted at different storage intervals.

The hetero‐fermentative bacteria i.e. Lactobacillus plantarum along with baker's yeast exhibited the best results regarding the utilization of sugars during fermentation (after 3 h of fermentation 0.0158 mg/ml sugar remained), objective evaluation of bread and its sensory characteristics. The bread prepared using the blend of hetero‐fermentative bacteria (0.5 per cent) and yeast (0.5 per cent) also showed greater resistance against bacteria (9×10¹ cfu/g after 60 h of storage) and mold (1.1 ×  10² cfu/g after 60 h of storage) growth.

Hetero‐fermentative bacteria along with baker's yeast can be utilized in sour dough to improve major bread characteristics. This study is a step further in improving the shelf life of sourdough.

Presently only baker's yeast is being used by bread industry for fermentation purpose but a blend of bacterial culture along with baker's yeast can give better performance for better quality and shelf life of the bread.

Probiotics are known to extend health benefits and therefore may be included during yoghurt manufacture to enhance its prophylactic properties. Different probiotic strains may exhibit diverse biotechnological behaviour in association with yoghurt cultures, therefore interactive behaviour amongst probiotic and yoghurt cultures must be evaluated prior to their commercial application. This paper aims to assess the effect of inclusion of different probiotic cultures on various biotechnological (technological, dietetic and prophylactic) characteristics of yoghurt cultures.

Yoghurt was assessed for technological characteristics based on acidification and flavour production, dietetic characteristics based on proteolytic activity, vitamin synthesis and L (+) lactic acid production and prophylactic characteristics based on β‐galactosidase activity, antibacterial spectrum, viability in product as well as during gastro‐intestinal transit, intestinal colonization, immunomodulation, anti‐carcinogenicity and hypocholesterolemic effect.

Different probiotic cultures exhibited diverse technological, dietetic and prophylactic behaviour in association with yoghurt cultures. Functional properties of traditional yoghurt could be enhanced with the combined introduction of probiotic cultures such as Bifidobacterium bifidum, Bifidobacterium infantis and Lactobacillus acidophilus and the resultant product may be recommended for consumption as a dietary adjunct.

The paper shows that combined introduction of probiotic cultures such as B. bifidum, B. infantis and L. acidophilus, as microbial additives during the manufacture of yoghurt would result in a product with enhanced functional properties.

The purpose of this paper is to evaluate effects of simultaneous supplementation of milk protein concentrate (MPC) as texture modifier and microencapsulated Lactobacillus paracasei (L. paracasei) (entrapped in gellan–caseinate) on physico-chemical, sensorial and microbial characteristics of yogurt during storage time.

L. paracasei cells were encapsulated through unique pH triggered gelation technique using combination of sodium caseinate-gellan gum as protective shell material. MPC was also used to improve physico-chemical indices of probiotic yogurt at different levels (0–3 percent).

The results showed that yogurt samples containing encapsulated L. paracasei showed lower post-acidification and higher viability. Samples containing encapsulated L. paracasei showed less syneresis amount, due to possible hydration of shell material, also application of MPC could reduce this attribute during storage time. The numbers of probiotic bacteria were remained above the recommended therapeutic minimum throughout the samples.

The findings suggest a practical ingredient in probiotic dairy product. Simultaneous usage of this kind of encapsulation via MPC enhanced sensorial and physical properties of probiotic yogurt while of no reduction in viable counts survival.

This study revealed usage of microcapsules of L. paracasei prepared by the gelation of sodium caseinate-gellan gum could be a suitable manner for delivery of probiotics in fermented dairy products like yogurt.

The purpose of this study is to evaluate the effect of almond milk supplementation on the growth and viability of Lacticaseibacillus rhamnosus GR-1 (LGR-1) in yogurt samples over 6 h of fermentation and 30 days of refrigerated storage.

Four yogurt treatments (T1–T4) were inoculated with the probiotic strain L. rhamnosus GR-1 and fermented for 6 h at 37°C and then placed in refrigerated storage at 4°C for 30 days. Microbial and pH analysis of each sample was conducted every 2  h throughout the fermentation period and on Days 1, 15 and 30 of cold storage to determine the viability of L. rhamnosus GR-1.

All samples achieved mean microbial counts of at least 108 CFU/mL during fermentation and storage. During fermentation, mean microbial counts increased for all treatments; however, differences in mean microbial counts between treatments were not significant. During storage, the mean microbial count for T4 at 15 and 30  days was significantly higher (p = 0.031) than microbial counts on Day 1. However, mean microbial counts did not differ significantly across all storage time points for treatments 1, 2 and 3 (p > 0.05). These results suggest that the addition of almond milk, in combination with cow’s milk, is suitable for propagating and preserving the viability of L. rhamnosus GR-1 in yogurt.

There is a consumer shift towards plant-based products due to health, environmental and ethical reasons. Almond milk is a popular nondairy alternative that provides enhanced nutritional value to traditionally dairy-based probiotic yogurts. L. rhamnosus GR-1 is an especially beneficial probiotic for women as it colonizes the gut and vaginal epithelium, promoting urogenital health, including preventing the recurrence of urinary tract infections and bacterial vaginosis.

Yoghurt consists of approximately 60 per cent of per capita dairy consumption of Iranian people. Iranian dairy factories use commercial starters which are expensive in yoghurt production. Moreover, yoghurt produced by these starters does not completely meet the taste of Iranian consumers. The aims of this study are to produce well qualified yoghurt from isolated native starters and to evaluate microbial, chemical and organoleptic characteristics of products.

The microflora of Iranian native yoghurts were isolated, purified and identified. The isolated strains were used as starter for the production of yoghurts. Sensory evaluation and measurement of pH, acidity and acetaldehyde content of the samples were carried out. Acidity, pH, acetaldehyde content, and microbial population of the best samples were measured during 21 days of cold storage. SPSS software was used for statistical analysis.

During the above mentioned storage period, acidity and acetaldehyde content increased significantly (p < 0.05). Significant decreases (p < 0.05) were observed in pH and microbial population. No significant difference in organoleptic characteristics (taste, smell and texture) were found after 21 days of cold storage.

Yoghurt production by native starter cultures instead of commercial ones is beneficial in respect of both economic and organoleptic aspects. The results indicate that the use of isolated native yoghurt starters in manufacturing yoghurt can be satisfactory and can also be extended to the production of yoghurt on an industrial scale.

Bioconcrete is widely believed to be environmentally beneficial over conventional concrete. However, the process of bioconcrete production involves several steps, such as waste recovery and treatment, that potentially present significant environmental impacts. Existing life-cycle assessments of bioconcrete are limited in the inventory and impact analysis; therefore, they do not consider all the steps involved in concrete production and the corresponding impacts. The purpose of this study is to extensively study the cradle-to-gate environmental impacts of all the production stages of two most common bioconcrete types (i.e. sludge-based bioconcrete and cement kiln dust-rice husk ash (CKD-RHA) bioconcrete) as opposed to conventional concrete.

A cradle-to-gate life-cycle assessment process model is implemented to systematically analyze and quantify the resources consumed and the environmental impacts caused by the production of bioconcrete as opposed to the production of conventional concrete. The impacts analyzed in this assessment include global warming potential, ozone depletion potential, eutrophication, acidification, ecotoxicity, smog, fossil fuel use, human toxicity, particulate air and water consumption.

The results indicated that sludge-based bioconcrete had higher levels of global warming potential, eutrophication, acidification, ecotoxicity, fossil fuel use, human toxicity and particulate air than both conventional concrete and CKD-RHA bioconcrete.

The contribution of this study to the state of knowledge is that it sheds light on the hidden impacts of bioconcrete. The contribution to the state of practice is that the results of this study inform the bioconcrete production designers about the production processes with the highest impact.

The quality of probiotic yogurt which is remarked as a healthy, therapeutic and nutritious food product strongly depends on starter types and their compositions; however, the choice of starter culture affects the taste, aroma and quality of the final product. Through this study, to obtain favorable quality attributes of probiotic yogurt, a mixture of two thermophilic/mesophilic starter cultures (YC- 350/YC- X16) was applied for fermentation.

The effects of starter mixture, probiotic Lactobacillus paracasei and storage time on quality indices, such as apparent viscosity, water holding capacity, syneresis, post acidification rate and probiotic viability (L. paracasei), were assessed through using a combined (mixture-process) statistical design.

The results revealed that changes in viscosity and syneresis depend on the amount of YC- X16. Acidification rate was more pronounced at higher levels of YC- 350 (1.22 per cent) in comparison to that in YC-X16 (1.08 per cent) during storage time. With respect to probiotic viability, L. paracasei count was more than 107 cfu/mL during refrigerated storage time. Moreover, a promotive effect of YC- 350 on L. paracasei proliferation was observed in this study.

The favorable yogurt, from qualitative aspects, was manufactured at 75:25 per cent ratio of YC- X16:YC- 350 in probiotic type yogurts. Therefore, the use of mixed starter cultures developed textural properties of probiotic yogurt beside L. paracasei survival.

Traditional fermented products can be adopted as probiotic carriers. This study was aimed at evaluating the potential of using Obushera, a traditional sorghum beverage from Uganda, as a carrier for Lactobacillus rhamnosus yoba.

Probiotic Obushera was produced by fermenting sorghum malt with Lb. rhamnosus yoba 2012 and Streptococcus thermophilus C106 at 30 °C and at room temperature (21°C-25 °C) for 24 h. Acidity, pH, total soluble solids and microbial counts were monitored. Consumer acceptability and purchase index of probiotic Obushera were compared to four commercial non-probiotic brands. Shelf stability of probiotic Obushera was determined by monitoring changes in pH, acidity, soluble solids, microbial counts and consumer acceptability during refrigerated storage.

Lactobacillus rhamnosus yoba 2012 multiplied and lowered the pH of Obushera from 5.3 to < 4.0 (p < 0.0001) whilst increasing acidity from 0.21 to 0.46 per cent (p < 0.0001) in 9 h at 30 °C. Consumer acceptability varied with Obushera brand (p < 0.0001). The overall acceptability score of probiotic Obushera (score of 6.4 = like slightly) was similar to that of the two most acceptable commercial brands (scores of 5.8 and 6.6). Acidity, pH and Lb. rhamnosus counts of probiotic Obushera varied within 0.6 per cent –1.05 per cent (p < 0.0001), 3.3–3.4 (p < 0.0001), and 8.2-9.2 log cfu/ml (p < 0.0001), respectively during two months of storage. The overall acceptability of probiotic Obushera (scores of 6.9-7.8) did not change significantly during storage (p = 0.185).

Traditional fermented foods such as Obushera can be adopted as carriers of probiotic microorganisms.

Use of commercial probiotic strains in traditional fermented foods is a novel approach that can be adopted to improve safety of traditional fermentations and health of consumers.

Prophylactic characteristics of plain acidophilus milk could be further enhanced with the incorporation of certain probiotic or beneficial organisms. This research undertakes to evaluate the technological and dietetic characteristics of probiotic acidophilus milk containing Bifidobacterium bifidum and Propionibacterium freudenreichii subsp. shermanii during storage.

The effects of incorporation of Bifidobacterium bifidum NDRI and Propionibacterium freudenreichii subsp. shermanii MTCC 1371 as microbial additives during the manufacture and storage of acidophilus milk made from skimmed milk at 8±1 °C for seven days were evaluated. Probiotic acidophilus milk was evaluated on the basis of various technological (titratable acidity, volatile acidity, diacetyl and acetoin production and extent of proteolysis) and dietetic (lactic acid content, lactose hydrolyzing activity, antibacterial activity, viable population of lactobacilli, propionibacteria, bifidobacteria) characteristics.

Probiotic acidophilus milk obtained with the conjugated application of Lactobacillus acidophilus R, Propionibacterium freudenreichii subsp. shermanii MTCC 1371 and Bifidobacterium bifidum NDRI retained its dietetic characteristics up to seven days of storage at 8±1 °C and its consumption may be advantageous over plain acidophilus milk due to its enhanced prophylactic features.

Mineral and vitamin estimation of probiotic acidophilus milk, animal and infant feeding trials must be conducted.

Conjugated application of Propionibacterium freudenreichii subsp. shermanii MTCC 1371 and Bifidobacterium bifidum NDRI as microbial additives during the manufacture of acidophilus milk may be suggested to enhance its prophylactic features.

Conjugated application of P. freudenreichii subsp. shermanii MTCC 1371 and B. bifidum NDRI as microbial additives with L. acidophilus R during the manufacture of acidophilus milk is suggested to enhance the prophylactic features of plain acidophilus milk. Consumption of probiotic acidophilus milk as a dietary adjunct can be recommended.