فصلنامه پژوهش و نوآوری در علوم و صنایع غذایی
سال یازدهم شماره 4 (زمستان 1401)

In this study, the effects of different amounts of carboxymethyl cellulose (CMC) (0 to 0.2%), cress seed gum (CSG) (0 to 0.2%), whey protein concentrate (WPC) (2 to 8%), and whipping time (WT) (2 to 8 min) on the physical and rheological properties of camel milk whipped cream were investigated. The results showed that with increasing the WT and WPC levels, overrun increased and samples with higher CMC had higher overrun than samples with higher CSG. The results also showed that the effect of different levels of WPC on the overrun of the samples was highly dependent on the whipping time and different concentrations of gums. With increasing the WPC and WT (in high WPC values), the foam stability of the samples increased and changing the ratio of CSG and CMC gums had no significant effect on the foam stability. The results of the back extrusion test showed that with increasing the WT and CSG, the hardness and adhesiveness of the samples increased. The results showed that with increasing the WPC and WT, the infinite and zero shear rate viscosities increased, while with increasing the WPC, the relaxation time of the samples decreased. The highest area of hysteresis was related to the samples containing the same amounts of CMC and CSG, but increasing the WPC reduced the area of hysteresis. To optimize the whipped cream formulation, the overrun, foam stability, hardness, consistency, and infinite shear rate viscosity were considered to be maximum, and adhesiveness and flow behavior index were adjusted to be minimum. According to the optimization results, the sample containing 0.15% CMC, 0.05% CSG, 2% WPC and produced with 7.2 min WT was the optimized formulation.

Lactic acid bacteria produce a large number of antimicrobial metabolites which are effective against pathogenic microorganisms. Amongst LAB’s antimicrobial agents, bacteriocins have been found as potentially safe biopreservatives. In this research, LAB isolates from less studied non-dairy fermented products were screened for simultaneous production of bacteriocins. Among 253 dominant isolates from 48 types of fruit and vegetable fermented products, strains which found to be potent bacteriocin producers were selected. Further, DNA of the strains was evaluated by the 16S rRNA sequencing. Five isolates identified as Lactiplantibacillus plantarum (10A, V3, S6, Sa, and Ab), showed the highest inhibitory effect against the growth of pathogenic indicators Listeria monocytogenes PTCC 1165, Escherichia coli ATCC 25923, Salmonella enterica serovar typhimurium PTCC 1609 and Staphylococcus aureus ATCC 25922. Response surface methodology was used to optimize the culture conditions based on various carbon/nitrogen sources in different temperatures (30, 32, 35, and 37 ºC) and incubation periods. This led to an increase in efficiency of bacteriocin production by 70%. The bacteriocin production curve was plotted within 58 hours showing that the maximum production and activity happened at 35 °C/48 h in culture containing peptone, yeast extract, tween 80 and glucose. Inhibitory effect of bacteriocins was significantly reduced when treated with proteolytic enzymes. Among the 5 isolated strains, 10A with an activity of 64000 Au/mL exhibited the highest inhibitory effect, even more than nisin. This study successfully recommends the selective potential of bacteriocin 10A as a candidate food biopreservative to control the growth of food pathogenic and spoiling bacteria.

This work was undertaken to develop a novelly formulated cake substituted with the cold-pressed Nigella Sativa oil and evaluate their nutritional properties namely Carbohydrate, Protein, Fat, Ash, Moisture, Energy, physicochemical properties, antioxidant activity, and shelf life of the savory cake. The formulated savory cakes in different proportions in ranges from 2.50 to 10% along with butter (SC1-2.50, SC2-5, SC3-7.50, and SC5-10%) as best suited for the recipe and without adding Nigella Sativa oil as taken control (SC0-0%). Results revealed that nutritional properties of carbohydrate, protein, fat, ash, moisture and energy of various concentrations of savory cake were reported significant differences (P<0.001) as compared to the control. The hardness of savory cakes increases even as the texture profile decreases with the continuing increase of Nigella Sativa oil. Color parameters, L*and a* values of the savory cake were decreased with the increase in the Nigella Sativa oil level. Scanning electronic microscopy reported the spongy structure of savory cake which dominance to increase in expansion ratio. The increased amount of Nigella Sativa oil in the dough formulation resulted in higher antioxidant properties in the final product and reduced lipid peroxidation. Sensory values were reported significantly increased in their acceptance among the savory cakes as compared to the control. The SC3 sample was observed to be most acceptable to sensory panelists towards the formulated cake. Based on the present work, Nigella Sativa oil-based baked products have good potential for consumer receipt, and health-promoting snacks, especially for diabetes patients.

This work investigates the development and optimization of cooking and heating systems. An experimental protocol for achieving energy-efficient cooking systems with a combined cooker and stove assembly is being developed. In conventional cooking practice, a pot or pan is put directly on a flame, and the thermal efficiency of these systems ranges between 20 and 25%. It was desired to boost efficiency to 70% or greater. This work studies the increase in fuel utilization efficiency and time reduction of the cooking vessel with different stacking arrangements of the cooking vessel. This study captured cooking vessels made of stainless steel with different central annulus geometries to improve the steam distribution. Items such as rice and dal have been cooked efficiently and uniformly through the steaming and boiling process. This device has saved fuel up to 30% and time by up to 40% of energy compared to conventional cooking practices. These works can be implemented in rural as well as urban areas and an expected to result in more social and economic benefits.

This research aimed to examine the potential of increasing the shelf life of Hypophthalmichthys molitrix (silver carp) fillets using basil seed gum-based film enriched by various concentrations (0, 0.5, 1, 1.5, and 2% /dry matter) of Echinophora platyloba extract (EPE) during a 16-day storage period. Each characteristic of basil seed gum-based films enriched by EPE followed a specific trend. The results showed that with increasing EPE, the film thickness, length to the rupture point, and antioxidant activity of film increased; however, the film with the highest concentration of EPE had the lowest solubility (19%) and tensile strength (15 MPa). The film loaded with 2% EPE overall presented acceptable physicchemical properties and was used for wrapping (optimum film). The fillets wrapped by the optimum film on the 16th day of storage indicated a lower total volatile basic nitrogen (TVB-N) value (36 mg N/100 g meat) compared to the nonenriched film (60 mg N/100 g meat) as well as the control sample (65 mg N/100 g meat). The fillet sample wrapped by basil seed gum-based film enriched with 2% EPE had lower pH and thiobarbituric acid index, peroxide index, and microbial load after 16 days of storage compared to the basil seed film sample without the extract and control sample. The obtained results encourage the use of basil seed gum-based film containing EPE in active food packaging systems to extend the shelf life of silver carp fillets.

DNA extraction is a crucial step in all nucleic acid-based protocols to identify microorganisms. Lactic acid bacteria are a significant part of healthy microbiota in the human gastrointestinal tract. These gram-positive bacteria have several layers of peptidoglycan in the cell walls. These structures cause difficulties in the cell lysis and obtaining reliable protocols for DNA isolations. The purpose of this study was to assess the autoclave and lysozyme-based DNA purification approaches for achieving the high-quality genomic DNAs of Lactobacillus acidophilus bacteria. DNA concentrations and qualities were also compared with the commercial kit. The results showed that the proper DNA isolation methods were various, according to the downstream applications. Protocols that included lysozyme produced a higher amount of DNA than the autoclave method. Lysozyme treatment combined with silica-guanidinethiocyanate procedure was the efficient protocol with affordable cost for routine lysis of L. acidophilus bacteria. Appropriate DNA concentration and quality were obtained through this method comparable to those of the commercial kit. Inversely, autoclave treatment had little effect on the breakage of the cell walls indicating low concentrations of extracted DNAs. This method could not completely break down all the bacterial cell walls. However, the breakage of low numbers of cell walls was microscopically observed in the supernatant of the autoclaved cell suspension. The quality of this protocol was found to be adequate for performing direct polymerase chain reaction (PCR) assay on samples with large amounts of lactobacilli. These conclusions suggest attentively selecting the DNA extraction method based on the planned downstream analysis of PCR products.

The physical, chemical and textural properties of cheese analogue depend on their source as well as the formulation conditions. Recently, cheese analogue has attracted the attention of consumers due to its nutritional, textural, sensorial and health properties. The aim of this study was to investigate the interaction effects of independent parameters such as rice milk (70 to 75%), chia seed (15 to 18%) and hazelnut oil (4 to 6%) to evaluate the optimal cheese analogue formulation using the response surface methodology. According to the obtained results, it was observed that with the increase concentration of independent variables, the overall acceptance of the samples initially increased and then showed a downward trend. Also, the textural characteristics of cheese analogue samples such as hardness, cohesiveness, springiness and gumminess showed rice milk and chia seed improved the textural properties, but the concentration of hazelnut oil had the negative effect on these parameters. The concentration of chia seed and hazelnut oil decreased L*, while the concentration of rice milk increased brightness index. The a* index showed a reduction trend in high concentrations of rice milk. The results observed that the optimum formulations of cheese analogue determined rice milk 71.87%, chia seed 17.62% and hazelnut oil 4.86%. Also, the estimated responses containing L*, a*, hardness, cohesiveness, springiness, gumminess, and total acceptability parameters were 68.08, 3.56, 4.79, 2.47, 1.42, 2.96 and 2.67, respectively. Generally, According to the results found in the present study, it can be concluded that the response surface methodology was able to predict the optimal of cheese analogue formulation with high desirability (0.85).

Roselle calyces (Hibiscus sabdariffa) are becoming very important in the food and beverage industry, especially because of the presence of anthocyanin which is an antioxidant responsible for their red colour. The effect of processing parameters such as contact time, temperature and calyx-water ratio on the anthocyanin content of roselle calyces extract was studied and optimized along with evaluation of kinetic models, mass transfer and thermodynamic parameters. Extraction kinetics for anthocyanin were obtained at different time (5, 10 and 15 min), temperature (30, 50, 75 and 100 °C) and calyx-water mass ratio (1:50, 1:20 and 1:10). The maximum anthocyanin yield was obtained at 15 min; 100 °C and ratio of 1:10. The data obtained were fitted to 6 different extraction models and the ones that best suited the data were Weibull type, Peleg and Pseudo-second-order with Adj. R2 of 0.98, 0.99 and 0.99 respectively. The data obtained were used to calculate the kinetic, mass transfer and thermodynamic parameters. The kinetic variables were also related to the fractional extraction or conversion model. The fractional extraction increased with increased temperature and calyx-water. The effective diffusion coefficient ranged between 1.04×10-11 to 1.48×10-11 m2/s. The mass transfer coefficient calculated ranged between 1.62×10-8 and 11.02×10-8 (m/s), Biot number ranges from 25 to 168. The thermodynamic properties: Activation energy ranged from 15.7 to 16.4 kJmol-1; the enthalpy from 36.60 to 58.30 kJmol-1; the entropy from 88 to 147 JK-1mol-1, and the Gibbs free energy from -5.80 to-11 kJmol-1. The extraction process was observed to be endothermic, feasible and spontaneous.