نشریه پژوهش های علوم و صنایع غذایی ایران
سال هجدهم شماره 3 (پیاپی 75، امرداد و شهریور 1401)

Nowadays, the quality of processed fruits or products is defined by a set of physical and chemical properties. In this study, due to the sensitivity of persimmon fruit to pressure, the parameters affecting the color changes of this fruit after pressure have been investigated. Three different coatings and packing materials and two loading were applied to study the color changes of the samples. Samples were stored in the refrigerator for 25 days. According to the results obtained for the value of L*, b*, Chroma index, Hue index and color changes, the use of 1 mM polyamine coating had a significant effect and caused less change than other coatings. Foil container packaging with polyolefin film has also been better packaged. The lowest percentage reduction for L*, a*, b* , Chroma index and Hue index  values was obtained in the 1 mM polyamine with a value of 8.26%, -26.43%, 12.35%, 1.31% and 120.995% respectively, Also the highest value was obtained in the uncoated state with a value of 18.49%, 73.32%, 19.84%, 15.95%, 152.36%. Finally, polyamine coating treatment has a positive effect to prevent the percentage reduction of color parameters of samples. The best coating treatment was polyamine with a concentration of 1 mM

In recent years, there has been an increasing interest in the application of plasma technology in food preservation technologies. Plasma is nonthermal physical processing that has a high potential in the field of  food processing. In this study, a mathematical model was investigated for yeast deactivation during plasma treatment. The definitive screen design was used to investigate the factors that affect yeast deactivation by plasma. Four factors of voltage (A: 20- 30 kV), Vessel diameter (B: 40- 60 mm), process temperature (C: 20- 40ºC), and type of plasma media (air or water) were selected. Then the treatment was simulated by COMSOL software. The responses of reaction kinetics coefficient, the ozone concentration, and final deactivation time were analyzed by definitive screen design expert to find the effective model parameters and process optimization. The results show that plasma treatment in water can have the strongest effect than air plasma. The changes in the number of microorganisms have a linear relationship with process time at different voltage- temperature conditions, but the ozone concentration dramatically changes at different combinations of voltage and temperature. The analyzed data show the kreac is affected significantly by the diameter of the vessel and the 221 types of process media (water or air). The ozone concentration only depends on the type of plasma media and the final 223 process time significantly depends on vessel diameter and type of media. Also, in plasma treatment, media type had a significant effect on all 3 responses, while the effect of temperature was only on final process time. For example, at temperature 20ºC the ozone concentration decreased at the first time of treatment and then stay constant, but at 30ºC, the ozone production increased with treatment time. This study showed when an RSM design was applied for designing the experiment which considers different process factors, the results can significantly differ from the study on only one-factor. In plasma treatment, media type had a significant effect on all 3 responses, while the temperature shows its effect only on final process time. Thus it can be concluded that with proper selecting of plasma media, this technology can be used for deactivation of food microorganisms

Forensic investigation is very crucial for identifying quality and safety issues related to food and its product. GC- MS has been used extensively in food analysis, and in the present study, it was used to identify the active constituents of some household spices as well as to detect the adulterants and contaminants which might be present in the samples. Spices used in the present study are black pepper, cumin, fennel, coriander and turmeric. The spice extracts were found to be useful in authenticating the spices by identifying various active constituents of the spices, like piperine, caryophyllene and 3- carene in black pepper; cuminaldehyde and 1, 3- methadien- 7- al in cumin; anethole and fenchone in fennel; linalool, and geranyl vinyl ether in coriander and turmerone and zingiberene in turmeric. The adulterants detected qualitatively were plant- based adulterants. GC- MS is proved to be an effective tool in detecting plant- based adulterants, microbial contaminants, and agro chemical residues as well as industrial and manufacturing waste.

This study aimed to investigate antimicrobial and antioxidant activities of borage (Echium amoenum L.) and hollyhock (Althaea rosea var. Nigra) extracts. The extracts were obtained through soaking and ultrasound- assisted methods using water or methanol as a solvent. The total phenols and flavonoid, anthocyanin content, free radical scavenging activity, ferric reducing antioxidant power, and antibacterial capacity of the extracts were determined. Phenolic acids were identified using the HPLC chromatogram. It was found that the ultrasound-assisted extraction was more efficient compared to the soaking method. The results showed that in the TPC, anthocyanins, and the FRAP tests, the highest amount was related to the samples extracted using the ultrasound- assisted method with water as solvent. The highest amount of TFC was obtained through a soaking method using methanol as the solvent. Anti- radical activity of the samples indicated that using water as a solvent in the optimum method resulted in a higher antioxidant activity. Furthermore, bacterial alpha amylase inhibition test signified that the inhibitory effect was boosted by increasing the extract concentration. The HPLC analysis of the borage and hollyhock extracts revealed that gallic acid and Syringic acid were the most prominent phenolic compounds. Generally, the results showed a good antibacterial property against Staphylococcus aureus for borage and hollyhock extracts. The results give us valuable insight into the potential therapeutic and medicinal applications of borage and hollyhock as a natural preservative to improve immunity.

The objective of this study was to improve the survival of lactic acid bacteria (LAB) in Tarhana soup as a non-dairy matrix. Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophiles were encapsulated in electrospun nanofiber mats fabricated from corn starch (CS) and sodium alginate (SA) and the protective effect of the nanofibers were investigated on the cells during the preparation of Tarhana and in the gastrointestinal tract. The moisture content of the control and nanofiber- loaded dried Tarhana samples was 8.75 and 8.71%, respectively; therefore, using nanofiber mats in the formulation had no significant effect  on the moisture content of the samples. A negative zeta potential value of -15.1 mV was found for LAB- loaded nanofibers. The nanofibers mats prepared from SA and CS mix showed a bead- free and clean structure with uniformity in size. The diameter size of most of the fibers ranged from 175- 338 with an average of 265 nm. Loading nanofiber mats with L. delbrueckii subsp. bulgaricus and S. thermophilus cells led to a uniform distributed beaded structure and the average diameter enhanced to approximately 763 nm. The viability of L. delbrueckii and S. thermophilus at the end of the electrospinning process was 92.82% and 95.83%, respectively, which indicating a slight loss in their population. Survival of nanoencapsulated S. thermophilus and L. delbrueckii was 93.50% and 89.16% respectively, while for free cells it was 85.3 and 76.4% that showed considerable protective effect of CS/SA fibers on the cells against dehydration of Tarhana medium. Nanofiber mats improved the stability of the cells against ordinary heat treatment used in preparing Tarhana soup. The survival rate of S. thermophilus was higher than L. delbrueckii subsp. bulgaricus and a significant difference was observed between the viability of free and nanoencapsulated bacteria. The survival of CS/SA nanoencapsulated S. thermophilus and L. delbrueckii subsp. bulgaricus was 83.25% and 80.21%, respectively, which is indicative of the significant protective effect of fibers on the cells against the heating process. The nanofibers also provided good stability for the cells in the gastrointestinal tract as 106 to 107 CFUg-1 of the cells were survived which is within the recommended level of potential probiotic dose to be effective. There was no significant difference in the color of all samples. Nanoencapsulation in CS/ SA nanofiber mats improved the protection of both LAB strains in simulated fluids of the stomach and intestine (Table 4). After continuous exposure to simulated gastrointestinal fluid, a significant loss of viable free LAB cells (higher than 4 log CFU/ml) was found while the population of S. thermophilus and L. delbrueckii subsp. bulgaricus encapsulated in CS/ SA nanofibers decreased only 0.45 and 0.37 log CFU after 120 min (p> 0.01), 0.93 and 0.80 log CFU after 180 min (p< 0.01), respectively. Tarhana soup prepared with probiotic– loaded nanofibers gained higher scores in terms of consistency, mouth feel, odor, taste, flavor, and overall acceptability attributes. Tarhana soup with nanofibers possessed much sour taste and flavor than samples prepared with free cells of probiotics. The results of the present study indicated that the protection obtained from CS/ SA capsules secured around106 to 107 CFU/g of the probiotic cells which are within the recommended level of probiotic dose to be functional in consumers’ body. Therefore, this product can be used by the consumers like vegetarians and lactose or milk peptide intolerants who do not consume dairy products but need potential fermented probiotic food.

Walnuts have a high nutritional value because of their high levels of  essential compounds for human health. Phenolic compounds have beneficial properties, including anti-cancer and antimicrobial properties. In this study, the amount of the extracted antioxidants from different parts of walnut, including the walnut kernel, hard shell and green husk by ethanol and water was compared with those of the ultrasound-assisted extraction. This study was performed by determining the amount of polyphenols present and the free radical scavenging power of DPPH. The results showed that the effect of all factors was statistically significant at 99% statistical level. The highest rate of extraction of phenolic compounds (1.09 mg Gallic acid/g) and the highest rate of free radical scavenging of DPPH (6.86%) was related to the use of ethanol solvent for extraction. It was also shown that the hard walnut shell has the highest amount of phenolic compounds (1.1 mg Gallic acid per gram of extract) and the walnut kernel has the highest antioxidant properties (7.99%). Ultrasonic pretreatment increased the extraction efficiency of phenolic compounds and antioxidant properties so that this process increased the extraction of phenolic compounds from the green husk of walnut by 1.22 mg Gallic acid/g and increased the antioxidant properties of the kernel walnut by 13.51% compared to other parts.