Alaa Kareem Niamah

The Food and Agriculture Organization (FAO) defines pesticides as any substance or combination of substances designed to prevent, destroy, repel, or mitigate pests. This includes vectors of disease...

Aim: The objective of this study is to enhance the flavor of bio-yogurt through the addition of threonine at various concentrations, and to evaluate its influence on the physicochemical, microbiological, and sensory characteristics of the product. Methods: To prepare bio-yogurt from cow’s milk, a probiotic starter culture comprising Bifidobacterium bifidum (Bb-12), Lactobacillus acidophilus (La-5), and Streptococcus thermophilus (ST) was used, both with and without the addition of the amino acid threonine at three concentrations: 1, 5, and 10 mg/100 mL milk. The bio-yogurt samples were then subjected to various physical, chemical, microbiological, and sensory analyses, and compared against a threonine-free control sample. Results: On the first day, the logarithmic counts of the probiotic starter cultures were 8.55–8.58, 8.33–8.34, and 8.53–8.57 log CFU/g for Bb-12, La-5, and ST, respectively; these values decreased to 7.01–7.03, 7.52–7.56, and 7.82–7.89 log CFU/g after 21 days. The concentrations of volatile compounds (acetaldehyde, acetoin, and diacetyl) in the threonine-enriched bio-yogurt ranged from 42.12 µg/kg to 49.40 µg/kg, 25.11 µg/kg to 29.02 µg/kg, and 3.09 µg/kg to 3.97 µg/kg, respectively, compared to the control sample, which exhibited concentrations of 38.23 µg/kg, 22.50 µg/kg, and 2.55 µg/kg, respectively. Sensory evaluation results indicated that the sample supplemented with 10 mg of threonine received the highest scores compared to the other samples. Conclusions: Our findings provide evidence of the value of supplementing bio-yogurt with threonine, as it does not alter its physicochemical properties. Furthermore, it does not adversely affect the total viable counts of probiotic bacteria but significantly improves the flavor profile and enhances consumer acceptability.

This study aimed to concentrate date syrup using infrared radiation (IRC) technology to achieve a final concentration of 65%, while evaluating its physicochemical and microbial quality and modeling its yield using artificial neural networks (ANNs). The results showed the superiority of the IRC technique over the conventional (CC) method, reducing processing time by 28.57% and achieving a 53.40% higher heating rate. The ANN model demonstrated high accuracy in predicting yield (R ² = 0.989), recording the highest yield of 69.13% at 1520 W and 95°C. The date syrup produced using IRC exhibited lower specific energy consumption, density, and electrical conductivity compared to the conventional method, along with improved color characteristics and an 11.09% reduction in browning index. The technique also achieved an increase in total soluble solids (TSS) to 65.81%, with a lower moisture content and a higher level of monosaccharides. From a health perspective, no microbial growth was recorded when using 1250W of power, while sensory evaluation showed no significant differences for consumers. Economically and environmentally, IRC technology reduced annual costs by 24% and increased the sustainability of the process by 51.57%. The study concludes that AI-powered infrared technology is an ideal possibility for producing high-quality date syrup in a sustainable manner.

Hyaluronic acid is a natural antioxidant derived from various sources, including microbial ones, and is utilised in multiple fields, including medicine, food, and cosmetics. A local isolate of Streptococcus thermophilus, cultured on whey medium, was used to produce hyaluronic acid, which was identified by the carbazole reaction, high-performance liquid chromatography (HPLC), and Fourier transform infrared (FTIR) spectroscopy. The antioxidant activity of hyaluronic acid was then evaluated by measuring the reducing power of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide removal, and ferrous ion chelation, in comparison with the synthetic antioxidant BHT. It was then used as an antioxidant to preserve sunflower oil for a 90-day storage period. The results showed that the hyaluronic acid production rate was 0.598 g/L, and that a concentration of 500 µg/ml of the acid (dissolved in saline solution) was most effective in scavenging DPPH free radicals and hydrogen peroxide, with scavenging rates of 68.14% and 72.08%, respectively, while the iron ion binding rate was 81.98%. The addition of hyaluronic acid extract to crude sunflower oil resulted in lower levels of oxidation, acidity, and thiobarbituric acid during storage periods of 30, 60, and 90 days. The study also showed that sunflower oil stored in transparent containers was more susceptible to oxidation than oil stored in opaque containers. Therefore, hyaluronic acid can be used as a natural antioxidant and an alternative to synthetic preservatives to preserve oils and extend their shelf life.

Research into bio preservation using lactic acid bacteria (LAB) as alternatives to synthetic additives has seen significant growth in response to the increasing consumer demand for natural food preservatives. In this study, the biochemical properties and antibacterial activity of Streptococcus thermophilus isolates isolated from commercial yogurt brands were thoroughly evaluated for use in bio preservation. Twenty isolates were obtained from local markets and various yogurt brands and subjected to comprehensive biochemical characterization. Their antimicrobial activity against twelve pathogenic bacterial strains was evaluated. Biochemical analysis demonstrated that all isolates exhibited the intrinsic characteristics of S. thermophilus : catalase-negative, oxidase-negative, and alpha-hemolytic, with optimal growth conditions ranging from 30 to 45°C and remarkable tolerance to a wide range of pH (4.2–9.6) and salt concentrations (2–4% NaCl). All strains demonstrated the ability to ferment lactose, sucrose, glucose, and maltose, but were unable to metabolize mannitol, melibiose, raffinose, and sorbitol. Antimicrobial screening showed that 70% of the isolates (14/20) exhibited significant inhibitory effects, with preferential activity against Gram-positive bacteria (overall inhibition rate: 33.3%). Listeria monocytogenes showed moderate sensitivity (inhibition zone of 1.7 cm), while S. aureus showed the highest sensitivity, with inhibition zones extending to 2.3 cm. A secondary screening based on acidification capacity found strain S5 from Kefil yogurt as superior, exhibiting the highest antibacterial activity (5.7 cm inhibition zone) along with the highest acidity yield (1.14%). These results confirm the enormous potential of yogurt-derived Streptococcus thermophilus strains as natural biopreservative. Furthermore, they address consumer demands for clean alternatives to synthetic preservatives by providing a systematic framework for strain selection and optimization in food preservation applications.

The objective of this research was to prolong the storage life of probiotic yogurt and facilitate its handling and transportation, in addition to preserving the physicochemical characteristics and vitality of probiotic bacteria within the permissible ranges, during storage periods. The results showed the possibility of preserving probiotic yogurt dried at three different temperatures of 40, 50, and 60 °C and pressures of 0.5 millibars to maintain its physical and chemical characteristics within acceptable ranges. The number of bacteria decreased during the storage period, but the number of bacteria that enabled them to perform their therapeutic function remained maintained. The moisture, protein, fat, carbohydrate, ash contents, pH levels, and total acidity of probiotic yogurt of 4 %, 30.01%, 1.4%,5 4.68%, 7.89%, 4.2, and 1.1%, respectively, were within acceptable ranges at different temperatures and storage periods. Several tests were conducted on dried yogurt samples, including X-ray diffraction, electron microscopy, and thermal analysis. This demonstrated the extent of the effect of temperature and the drying process on the structure of dried probiotic yogurt after reconstitution and the extent of its effect on the bonding of the yogurt components with each other.

Streptococcus thermophilus is a Gram-positive, homofermentative lactic acid bacterium classified within the Firmicutes phylum, recognized for its probiotic properties and significant role in promoting human health. This review consolidates existing understanding of its metabolic pathways, functional metabolites, and diverse applications, highlighting evidence-based insights to enhance scientific integrity. S. thermophilus predominantly ferments lactose through the Embden-Meyerhof-Parnas pathway, resulting in L(+)-lactic acid as the primary end-product, along with secondary metabolites including acetic acid, formic acid, and pyruvate derivatives. Exopolysaccharides (EPS) are composed of repeating units of glucose, galactose, rhamnose, and N-acetylgalactosamine. They display strain-specific molecular weights ranging from 10 to 2000 kDa and contribute to the viscosity of fermented products, while also providing antioxidant and immunomodulatory benefits. Aromatic compounds such as acetaldehyde and phenylacetic acid are products of amino acid catabolism and carbohydrate metabolism, playing a significant role in the sensory characteristics observed in dairy fermentations. Bacteriocins, such as thermophilins (e.g., Thermophilin 13, 110), exhibit extensive antimicrobial efficacy against pathogens including Listeria monocytogenes and Bacillus cereus. Their activity is modulated by quorum-sensing mechanisms that involve the blp gene cluster, and they possess significant stability under heat and pH variations, making them suitable for biopreservation applications. In food applications, S. thermophilus functions as a Generally Recognized as Safe (GRAS) starter culture in the production of yogurt and cheese, working in conjunction with Lactobacillus delbrueckii subsp. bulgaricus to enhance acidification and improve texture. Specific strains have been identified to mitigate lactose intolerance, antibiotic-related diarrhea, and inflammatory bowel diseases through the modulation of gut microbiota, the production of short-chain fatty acids, and the inhibition of Helicobacter pylori. The genome, characterized by a G + C content of approximately 37 mol%, facilitates advancements in Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas technology and heterologous protein expression, with applications extending to non-dairy fermentations and the development of postbiotics. This review emphasizes the adaptability of S. thermophilus, showcasing the variability among strains and the necessity for thorough preclinical and clinical validation to fully utilize its potential in health, sustainable agriculture, and innovation. It also addresses challenges such as susceptibility to bacteriophages and limitations in proteolytic activity.

The present study aims to produce dried probiotic yoghurt using an infrared oven. A therapeutic starter consisting of three species: Lactobacillus acidophilus, Bifidobacterium bifidum, and Streptococcus thermophilus was used. The product was then dried at 50°C, and the physicochemical, microbial, and sensory properties of the dried yoghurt were studied during refrigerated storage. The results demonstrated the possibility of preserving probiotic yogurt dried in an infrared oven at 50 °C at refrigerator temperature, while, the moisture, protein, fat, carbohydrate, ash, total solids, pH levels and total acidity of probiotic yoghurt (5.91%, 31.92%, 1.45%, 51.51%, 8.21%, 94.09%, 4.34, and 0.98%, respectively) after 1 day of storage time. The log number of starter bacteria was 8.30, 6.73, 6.62, and 6.30 CFU/g for Lactobacillus acidophilus, Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium bifidum, respectively. The sensory evaluation results of the infrared oven-dried yoghurt samples on the first and last days of storage at refrigerator temperature were similar to the results of the air oven-dried yoghurt samples. Finally, drying the probiotic yoghurt in an infrared oven at 50°C yielded a dried product containing a high number of probiotic bacteria and exhibited good physicochemical properties after 3 months.

Biotechnology has emerged as a promising tool for the management of agri-food wastes (AFWs). The applications of biotechnology in this area are diverse and include the use of microorganisms and enzymes for the production of value-added bioproducts/byproducts (VBPs), the conversion of AFWs into bioenergy, and the reduction of environmental pollution. One of the main applications of biotechnology in the management of AFWs is the production of VBPs. Microorganisms and enzymes can be used to convert AFWs into useful VBPs such as biofuels, bioplastics, and enzymes. This approach not only helps to reduce AFWs but also creates economic opportunities by generating new VBPs from AFW materials. Another application of biotechnology is the conversion of AFWs into bioenergy. Biogas, which is a renewable energy source, can be produced from organic AFW materials such as agricultural residues, food waste, and animal manure through the process of anaerobic digestion. Biogas can be used to generate electricity, heat, and fuel for vehicles, thereby reducing dependence on fossil fuels. Biotechnology can also help reduce environmental pollution caused by AFWs. For example, microorganisms can be used to degrade organic pollutants in wastewater, reducing the environmental impact of AFWs discharge. Additionally, bioremediation techniques can be used to clean up contaminated soil and water by harnessing the natural abilities of microorganisms to break down pollutants. In summary, biotechnology has many applications in the management of AFWs, including the production of VBPs, the conversion of AFWs into bioenergy, and the reduction of environmental pollution. These approaches not only help to reduce AFWs but also create economic opportunities and promote sustainable development.