Iranian Food Science and Technology Research Journal

Abstract In the past decade, the food industry has seen increased focus on diverse and practical designs. Accordingly, this research aims to use additive manufacturing to create gel structures from a new perspective. In this study, quinoa protein (QP), either untreated (B) or treated with cold plasma (CP) or pulsed electric fields (PEF), at two concentrations (9 and 12% w/w), was combined with polysaccharides (alginate and agar) to prepare gels. The printability and physicochemical (water activity, dry matter, water holding capacity, and color analyses), textural, and rheological properties of gels were then compared. Evaluation of the textural properties revealed that the highest hardness was observed 530.27, 416.52, and 334.82 g for the 12% B, 12% CP, and 9% PEF samples, respectively. However, in examining the results of the frequency sweep, 9% and 12% CP had the lowest storage modulus among the other gels. The 3D printing results of gels indicated that they are printable and showed high stability over 24 hr. In addition, phase separation did not occur in all treatments when gels were exposed to severe stress. Therefore, optimizing quinoa protein gels for 3D printing requires coordinating processing parameters with the composition of the formulation. This could advance the development of novel food designs with enhanced texture and stability, aligning with the food industry’s focus on innovative and practical solutions.

Abstract Enzymatic browning processes negatively influence many food products, such as fresh juices, particularly their sensory properties and nutritional value, ultimately leading consumers to reject such products. Natural antioxidants have been used to reduce this phenomenon, preserving these products and preventing quality deterioration. This research investigates the antioxidant and enzyme inhibitory activities of eggplant peel ethanolic (EEPE) and aqueous (AEPE) extracts, by scavenging DPPH radicals method in mango juice (MJ) during cold storage. EEPE had greater DPPH radical scavenging capacity (0.66 mg/g) than AEPE (0.52 mg/g), although both extracts were weaker than vitamin C (0.73 mg/g). Enzymatic browning assays revealed that EEPE suppressed PPO and POD activities in mango juice (MJ), contributing to decreased browning intensity and better preservation of phenolic content after 15 days storage at 4°C, more than AEPE. Purified mango pulp PPO was of approximately 54 kDa molecular weight and was effectively extracted and purified using ammonium sulfate precipitation, dialysis, and CM-Cellulose ion exchange chromatography with a purification fold value of 15.07. Kinetic studies revealed that EEPE acted like a competitive inhibitor of PPO, while AEPE exhibited non-competitive inhibition. This finding reflects the potential of eggplant peel,as an agricultural waste, is a potent natural substance to be used in food preservation due to its antioxidant and anti-browning activities.

Abstract The protein with a gel like structure, extracted from collagen, is named isinglass, which is derived from the swim bladder of various fish, but is mostly extracted from sturgeon. Isinglass extracted from three types of sturgeon fish, which are commonly reared in Iran, namely Beluga, Persian, and Stellate sturgeon fish, using two different methods, namely the Indian method and the semi-industrial method. In this study, the extracted isinglass was tested for quality in terms of physical, chemical, microbiological, and organoleptic properties for 7 months at room temperature. The percentage of extraction as well as the extraction time were found to be higher in the semi industrial method (63-67% and 3-7 days) than in the Indian method (<24% and 8-24 days). (P<0.05). The protein content in semi-industrial method was 74-75%, while in the Indian method, it was about 64%. Moisture, TVB-N, and peroxide were better in the semi-industrial method compared to the Indian samples after 7 months. The semi-industrial samples had the lowest bacterial count, and their sensory evaluation showed higher acceptability scores compared to the Indian samples (above 4 after 7 months). However, the Indian samples were not acceptable in terms of sensory evaluation. The Indian samples had higher nutritional values and lower energy consumption, the semi-industrial method had higher yield, better chemical and microbial quality, and good sensory quality. Thus, it is concluded that semi-industrial method is a better choice for isinglass production on a large scale.

Abstract Dairy industry waste, particularly organic-rich dairy sludge, represents a promising and sustainable resource for biotechnological applications. This study evaluated the potential of dairy sludge as a cost-effective medium for the co-production of biomass and exopolysaccharides (EPS) by selected Enterococcus strains. The physicochemical parameters of the dairy sludge were characterized, revealing a composition of 32.70% fat, 29.32% protein, 9.56% ash, and 30.17% carbohydrates (which adjusted to 28.50% after spray-drying). Five strains of Enterococcus were screened through a quantitative culture-dependent approach to evaluate their growth and EPS production. Among the tested isolates, Enterococcus durans K48 exhibited the highest production potential and was selected for further study. Response Surface Methodology (RSM) was employed to optimize the concentrations of key medium components: dairy sludge, sucrose, and yeast extract. Under the optimized conditions (15% dairy sludge, 5% sucrose, and 2.5% yeast extract), a maximum biomass yield of 8,440 mg/L and an EPS yield of 394.2 mg/L were achieved. These findings demonstrate that dairy sludge can serve as a valuable source and sustainable substrate for Enterococcus cultivation, facilitating efficient biomass and EPS production while contributing to the valorization of dairy processing waste.

Abstract Calabash (Crescentia cujete L.) fruit has increasingly been studied in recent years for its significant contribution to human health and well-being. The reported bioactivities are linked to the presence of phytochemicals such as polyphenols, but little is known about the role of their proteins. This represents a significant gap, as fruits are generally overlooked as sources of proteins compared to legumes and other proteinaceous products, despite their potential functional and therapeutic applications. This study aimed to isolate, purify, and characterize proteins and peptides from calabash fruits, and evaluate their potential antihypertensive and lipid-lowering activities. Proteins were extracted, purified, and characterized through a combination of biochemical techniques such as sodium phosphate buffer extraction, ammonium sulfate precipitation, gel-filtration chromatography, and in vitro biological assays namely pancreatic lipase inhibition, cholesterol micellar solubility inhibition, and angiotensin-converting enzyme (ACE) inhibition assays. Crude protein isolate (CPI) had a protein concentration of 688 µg/mL with observed protein bands at 12.1 kDa to 46.7 kDa. After simulated gastrointestinal digestion, CPI showed average inhibition activities of 76.5% for ACE, 22.3% for pancreatic lipase, and 84.0% for cholesterol micellar solubility, while the 2-h digest of the purified protein fraction showed 73.4%, 44.9%, and 82.2% inhibition, respectively. Proteins and peptides exhibited strong bioactivity, with inhibition responses across all assays approaching those of the assay controls under the tested conditions. This is the first study to demonstrate the bioactive potential of proteins and peptides extracted from C. cujete fruit, providing promising insights into their possible functional properties associated with the preventive management of obesity, cholesterol levels, and hypertension. Further peptide fractionation and sequence identification are needed to confirm the most active components.

Abstract The present study examined the impact of replacing rice flour with sprouted oat powder (SOP) at various levels (0–100%) on the physicochemical, textural, and sensory attributes of gluten-free rice cake. Rheological analysis revealed pseudoplastic behavior, with apparent viscosity (AV) decreasing as shear rate increased, while higher levels of SOP resulted in increased batter viscosity. The inclusion of SOP led to reduced lightness index (L*) in both batter and cake, with the lowest lightness recorded in the 100% sprouted oat sample. Batter yellowness index (b*) increased significantly with substitution, while redness index (a*) showed no consistent trend. Sprouted oat substitution significantly increased cake weight and reduced baking loss. However, it had no statistically significant effect on cake volume or density. Cakes formulated with higher levels of SOP exhibited increased moisture (from 17.93% to 21.76%) and ash content (from 1.08% to 2.08%), reflecting the nutritional richness of the sprouted flour. The maximum acidity (0.83%) and minimum pH (6.73) were recorded in the sample prepared with 100% SOP. Increasing the concentration of SOP led to a systematic elevation in both the antioxidant potential and the total phenolic levels within the gluten-free cakes. The protein content of the final cakes also increased proportionally (up to 4.49% in the 100% oat sample), while the fat content remained relatively stable across formulations. Increased replacement ratios elevated cake crust hardness (from 0.04 N to 0.55 N), while texture profile analysis (TPA) results indicated no significant changes in crumb firmness or cohesiveness. Sensory evaluation revealed that up to 75% substitution was acceptable without negative impacts on aroma, flavor, texture, or overall acceptance, whereas higher replacement ratios negatively affected crust and crumb color.