مجله علوم و صنایع غذایی ایران
سال بیست و دوم شماره 3 (پیاپی 160، Jun 2025)

With the growing tendency of people to consume organic dairy products, there is always a risk of pathogenic microbial strains in unhygienic locally prepared products. Local sheep yogurt as an organic product is one of the most valuable dairy products in Iran.

The aims of this study were molecular and phenotypic identification of lactic acid bacteria (LAB) isolated from sheep yogurt from Hamadan and investigation of their pathogenic characteristics.

The LAB isolated from yogurt samples were identified phenotypically and molecularly by PCR amplification of the 16S rDNA region and subsequent sequencing. The pathogenic and safety characteristics of the isolates including antibiotic resistance, blood hemolysis, amino acid decarboxylase, DNase, and gelatinase activities were then investigated.

Forty-seven bacteria were isolated from yogurt samples, and only 22 gram-positive isolates reacted negatively to catalase. Based on the results, the isolates were molecularly characterized as 4 Lactobacillus helveticus, 5 Enterococcus mori, 2 Streptococcus salivarius subsp. thermophilus, 5 Lactobacillus kalixensis, and 6 Lactobacillus delbrueckii subsp. bulgaricus. Phenotypic identification also confirmed the isolates assigned to S. thermophilus and L. bulgaricus by molecular identification.

The evaluation of the pathogenic characteristics of the species associated with yogurt production, S. thermophilus and L. bulgaricus, confirmed that two isolates (HL1, HL2) of L. bulgaricus are safe as starter culture for yogurt production.

Extensive research has been conducted on the antioxidant properties of bamboo seed extract, particularly from the Bamboo (subfamily Bambusoideae) Linn plant. Due to their high antioxidant content, bamboo seeds have garnered interest for their potential health benefits in combating age-related chronic illnesses such as diabetes, cancer, Alzheimer's, Parkinson's, and cardiovascular disease. The consumption of bamboo-derived products on a daily basis may play a role in reducing the risk of developing these conditions. Antioxidants play a crucial role in the food and pharmaceutical industries, as they help counteract free radicals that can degrade products during processing and storage. The chemical components of the ethanol extract of Bamboo seed variety were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS), identifying twenty-four compounds. These included compounds such as 9,12-Octadecadienoic acid (Z,Z)-, Hexadecanoic acid ethyl ester, and Tetradecanoic acid -12-methyl- methyl ester, which were found in both Bambusa arundinacea and Dentrocalamus strictus. Furthermore, Linoleic acid ethyl ester and Octadecanoic acid were predominant in Bambusa arundinacea, while (E)-9-Octadecenoic acid ethyl ester, n-Hexadecanoicacid, Oleic Acid, and 12-Methyl-E,E-2,13-octadecadien-1-ol were found in Dentrocalamus strictus only. Other phytonutrients were also present in bamboo seed varieties, indicating their potential use in the treatment of various diseases as antioxidants and as a viable rice substitute.

In recent decades, there has been a shift towards using alternative methods to enhance traditional milk processing techniques and their derivatives. One such method is the application of ultrasonic treatment as a substitute for conventional pasteurization. The chemical content of milk treated with ultrasonic waves (US) for durations of 5 and 10 minutes at a frequency of 20 kHz and a temperature of 50°C showed increases in protein, fat, and acidity levels after 5 minutes of US pasteurization, registering at 3.50%, 3.65%, and 0.19% respectively, while the ash content was 0.73%. The logarithm of total microbial counts in milk samples showed no growth post-US pasteurization. The active compounds in the milk samples were identified using GC-MS, revealing the highest concentrations after 5 and 10 minutes of US treatment were of Hydroxy-2,8-bis(trifluoromethyl)quinoline, 2-methylpropionate 4- and Succinic acid, 3-methylbut-2-yl 3-chlorophenyl ester, at concentrations of 31.826% and 35.318% respectively. Samples treated for 10 minutes exhibited superior firmness, cohesiveness, and elasticity in soft cheese, with values of 179.9, 0.66, and 4.38, respectively. The lowest pH observed in these samples was 4.60, with the highest acidity at 1.68%. Moreover, ultrasonic treatment enhanced the sensory characteristics of the cheese, demonstrating that ultrasound waves can improve the microbial, physical, chemical, and sensory properties of white cheese.

This study evaluated the physicochemical properties of Prosopis juliflora pods and the preparation of its protein isolate. Changes in functional properties were observed when pH levels were adjusted to 5, 7, 8, and 10, with significant differences (P≤ 0.05) in functional characteristics and antioxidant and antibacterial activities. A high solubility value was achieved at pH 5.10 and lipid binding at pH 10, while the lowest value for both properties was found at pH 7. The highest foaming capacity was observed at pH 5 after 5 minutes of whipping, but decreased after 1 minute at pH 8. The emulsifying capacity was greatest at pH 10 and lowest at pH 7. The DPPH radical scavenging activity was high at pH 5, but decreased at pH 8 and also protein isolate showed inhibition activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. However, the highest inhibition was against Bacillus bacteria at 0.5% protein isolate concentration, while the protein digestibility was higher. The isolated protein had no noticeable cytotoxic effect on human blood cells. Besides, FTIR test was used to determine the structure of the protein.

The current study aims to enhance work in the field of isolating microorganisms that produce enzymes with practical uses, sustainability and food industries, by isolating and identifying lactic acid bacteria strains from different sources, some of which contain cellulose, which microorganisms depend on, primarily for their nutrition and reproduction, and which is present in the environment in which they are found, and the possibility of producing the enzyme Cellulase, which is considered one of the important enzymes in the analysis of polysaccharides (cellulose) and the production of monosaccharides and simple sugars. This study included the isolation and identification of Lactobacillus bacteria from different sources, purification, screening, identification and determination of their efficiency in producing cellulase enzymes. The results showed that fifteen isolates were obtained from various sources including soil, fruits, vegetables, pickles, dairy products and live fish entrails. Agar MRS medium with 0.5% (w/v) CaCl2 granules was used to isolate lactic acid bacteria, which were identified by phenotypic, biochemical and Gram staining tests.The optimum temperature for production is 35 °C with an enzymatic activity reached (3.425) and Specific activity (4.502), the pH value was 6 with the enzymatic activity reached (3.437) and Specific activity (4.399), the enzymatic activity was (3.419), and specific activity was (4.804), a fermentation time of 72 hours with an efficiency of (3.065) and Specific activity (4.305),the best carbon source cellulose with an efficiency of (5.44), and the best Nitrogen source wheat bran with an efficiency of (3.634) and a inoculum content of 5% with an efficiency of (3.399).

In response to the detrimental effects of dietary fat on consumer health, particularly its association with cardiovascular diseases, obesity, and various other health-related issues, there has been a concerted effort in contemporary food production to develop low-fat food products. The objective of  study is  evaluate the production of low-fat mayonnaise with oil content levels of 20%, 25%, and 30%. This investigation employs modified potato and corn starches at concentrations of 2. 5%, 3%, and 3. 5% The aims to systematically assess the relative impact of these formulations on  parameters, including viscosity, pH, acidity, stability, and physical properties, throughout  storage period of six months. Additionally, sensory properties will be evaluated to provide a comprehensive analysis of the product's quality and consumer acceptability. The findings indicated that the incorporation of both starches and elevated fat levels resulted in significant increases in pH values, viscosity, emulsion stability, tissue stiffness,  the adhesion properties of mayonnaise, concurrently leading to a reduction in the acidity of the samples. During the storage period at refrigeration temperatures, a significant reduction in viscosity, pH, firmness, and tissue adhesion was observed in the mayonnaise samples, accompanied by an increase in acidity and creaminess (p<0. 05) The findings from the sensory evaluation demonstrated that elevated levels of starches and fats significantly improved the scores of sensory parameters (p < 0. 05) The sensory evaluation revealed that the formulation of low-fat mayonnaise, which comprised 30% fat and 3. 5% modified potato starch, exhibited the highest level of sensory acceptance among the tested samples. The present study demonstrated that low-fat treatments utilizing modified potato starch exhibited superior quality characteristics in comparison to samples incorporating corn starch. In conclusion, the incorporation of 30% fat and 3. 5% modified potato starch as a fat substitute yields beneficial physicochemical and sensory properties in mayonnaise.

In this research, Lallemantia royleana seed mucilage was used as the base of the film, while essential oil derived from the zoulang plant’s leaves and stems, along with zinc oxide nanoparticles (ZnO), were incorporated as additives to develop active edible films. Findings indicated that incorporating ZEO enhanced the films' antioxidant capabilities, permeability, thermal properties, tensile strength, and elongation of the film. FT-IR analysis confirmed the creation of new hydrogen-oxygen bonds between ZEO and the polysaccharide chains, contributing to a reinforced film structure. Conversely, the addition of ZnO nanoparticles was found to decrease the antioxidant properties, permeability, crystallinity, thermal resistance, moisture content, and tensile strength of the films. Additionally, ZnO nanoparticles contributed to enhanced plasticity, which increased the films' stretchability and resulted in greater thickness. SEM imaging verified the interaction between ZEO and ZnO nanoparticles, aligning with the findings from the FT-IR analysis. Overall, the study suggests that films developed using Lallemantia royleana mucilage, in combination with ZEO and ZnO nanoparticles, demonstrate strong potential for applications in food packaging and active films or coatings, particularly for materials vulnerable to oxidation.

This study aims to investigate the physicochemical and mechanical properties of edible films prepared from sodium alginate at concentrations of 0.5% and 1%, with glycerol as a plasticizer at concentrations of 10%, 30%, and 50%. Thickness, tensile strength, percentage elongation, water solubility, water vapor permeability, light permeability, transparency, and antioxidant activity were evaluated. Results showed that the thickness, elongation percentage, water solubility, and water vapor permeability of the films increased with the rise in glycerol concentration from 10% to 30%. In contrast, tensile strength, water solubility, light permeability, and transparency decreased when the sodium alginate concentration was increased to 1% at the same glycerol concentrations. Antioxidant activity increased with higher sodium alginate concentrations at the same levels of glycerol. Hence, sodium alginate can be used as a natural component in food or pharmaceutical industries.