مجله علوم غذایی و تغذیه
سال بیست و یکم شماره 1 (زمستان 1402)

Chicken meat is one of the important and healthy sources of protein in the diet. Therefore, due to its high consumption, its preparation and cooking methods should be taken into consideration. Frying process is one of the most common operations in the food industry. In this method efforts have been made to obtain products with low oil content. Hot air frying is a new method of frying in which products are processed through direct contact with hot air and oil droplets in the frying chamber.

In this research, a hot air fryer was used to process chicken fillets. The response surface method was employed to model and obtain the optimal conditions of the hot air frying process. The effect of process parameters (temperature of 160,180,200 degrees Celsius, time of 10, 20 and 30 minutes and air flow speed of 1.5, 2.5 and 3.5 m/s) on the characteristics of the final product (Moisture content, fat content, evaluation of color parameters, crispness and sensory evaluation) were evaluated in order to achieve the optimal conditions of the process.

The results showed that the moisture content, crisp texture of the product and changes in the color of the product are affected by the temperature and duration of the process and increase with the increase of the parameters. The variables of air flow speed, temperature and process time have a significant effect on the fat content in fried chicken fillets (P≤0.05) and show an increasing trend.

Based on the results of the tests, the optimal conditions for frying with hot air temperature of 200 degrees Celsius, air blower speed of 1.50 meters per second and time of 22.87 minutes were determined.

One of the significant contaminants in animal-derived foods, such as milk, is antibiotic residues, which put consumers' health at risk. Monitoring the amount of antibiotic residue in milk is crucial in order to alert the nation's health authorities and in this regard, several researches have been conducted for determination of different antibiotic residues in milk using various traditional and chromatographic methods. In this study, an efficient method for determining the residual levels of some sulfonamides in pasteurized milk was developed and presented.

After dispersive solid-phase extraction combined with air-assisted liquid-liquid microextraction of analytes, the residues of sulfadiazine, sulfamethoxazole, and sulfamethazine in the pasteurized milk were determined using HPLC with a diode array detector. Following the evaluation of the effective factors in the extraction and optimizing them, the validation of method was carried out by calculating analytical parameters such as linear range, LOD, LOQ, repeatability, and extraction recovery.

In the developed two-step extraction method, satisfactory figures of merit were obtained, therefore the method's linearity was shown with a coefficient of determination higher than 0.995. The limits of detection and measurement were less than 1.2 and 3.2 ng ml-1, respectively, which is less than the MRLs established for these antibiotics in milk. The analysis of real samples showed the presence of sulfamethoxazole in three milk samples in concentrations of 13±0.1, 9±0.2 and 9.6±0.5 ng ml-1 and no other antibiotics were discovered in the examined samples.

Overall, the established approach is a sensitive, accurate and reliable method and has high efficiency in determining selected antibiotics in milk samples.

Flavor is one of the most important characteristics of food, which is directly related to the acceptance of the product by consumers. The increasing trend in the consumption of food flavoring compounds has motivated the production of food flavors therefore the global demand for natural flavors and aromas is continuously increasing. Plants and microorganisms are the main sources of flavor and aroma compounds such as terpenoids, aldehydes, methyl ketones, but due to their production in lower concentrations, the isolation and extraction of such value-added chemicals is expensive. Therefore, the biotechnological production of flavor compounds has been considered.

In the last decade, research has been carried out in the field of biological production of flavoring compounds. In this study, main biotechnological methods including the use of enzymes, microorganisms, tissue plants and cell culture have been investigated.

Conventional techniques for producing flavor compounds are not sufficient in terms of quantity and variety due to the rising market demand. Current flavor production methods use chemical synthesis, which can produce a greater number of flavors in less time. However, the demand for natural products has created the need for new methods to produce flavoring compounds labeled as natural origin. Biotechnological production is an attractive alternative to flavor production because it occurs under mild conditions, has high selectivity, produces no toxic waste, and produces products that can be labeled as "natural." Natural flavoring compounds obtained by biotechnological processes play an increasing role in the food, cosmetic, chemical and pharmaceutical industries due to the increasing consumer demand for natural food additives.

Emerging techniques in biotechnology have enabled industries to produce compounds that might be considered natural. There is no doubt that these technologies will become more important factors in the production of flavoring chemicals in the future due to their many advantages.

The high mobility and solubility of cadmium pose a serious threat to the health of humans and other organisms. There are no signs of toxicity when cadmium metal accumulates in the tissues of plants and enters the human food chain. Cadmium transfer rates from vegetables to the human diet depend on their accumulation. Thus, inorder to investigate heavy metal absorption by lettuce, this research evaluated the levels of cadmium accumulating in various lettuce organs.

The seeds of lettuce (Lactuca sativa Linn) were cultivated in autoclaved pots containing perlite and cocopeat (with a ratio of 2 to 1). The pots were kept under greenhouse conditions of 25±1 (day temperature) and 20±1 (night temperature) and light/dark conditions were placed. About three weeks after the plants reached the three-leaf stage, the seedlings were treated with cadmium chloride in 3 replicates. Four concentrations (0, 30, 60 and 90 μg/g perlite) were used every 3 days. After 5 stages of treatment and 28 days after cultivation, the third leaf of the plants was used for the studies.

Cadmium increased lettuce's phenol, flavonoid and antioxidant content significantly as compared to the control sample. Furthermore, by increasing the concentrations of cadmium, lettuce showed an increase in total protein, soluble sugar, free amino acids, proline, malondialdehyde, and hydrogen peroxide as compared to the control sample. Due to the increasing amount of cadmium applied to lettuce plants, an increase in the amount of cadmium in the roots was greater than in the aerial parts.

In general, the results of this research indicated that lettuce is a cadmium accumulating plant with the ability to accumulate heavy metals in its roots and aerial parts. Contaminated with heavy metals, it seems necessary to protect the health of consumers.

Coated foods are consumed in restaurants and homes immediately or shortly after preparation. This study was conducted with the aim of microencapsulating baking powder with carnauba wax in tempura formulation and investigating the changes of tempura powder during storage. Finally, its effect on the characteristics of coated chicken was investigated.

Baking powder was microencapsulated with carnauba wax at a ratio of 1:1. Tempura powder was prepared in three groups: T1 (control), T2 (tempura + 3% free baking powder), T3 (tempura + 3% encapsulated baking powder) and after comparing the physicochemical characteristics were used in preparation coats and evaluated for chicken fillet.

An increase in fat content, ash, and higher CO2 production, as well as a decrease in aw and protein in T2 and T3 treatments as compared to the control sample (p<0.05). The use of tempura powder with a new formulation significantly prevented the increase of peroxide in the samples during frying (p<0.05). Also, dough absorption and higher porosity were reported in the coated T2 and T3 samples as compared to the control (p<0.05).  A decrease in L* and increase of a* and b*was also reported in these treatments (p<0.05). A decrease in texture stiffness was reported in tempura-coated products (p<0.05). The highest score in the investigated parameters (taste, aroma, color, texture, and overall acceptance) was reported in T2 and T3 treatments (p<0.05).

Microencapsulation of baking powder is a promising method to prepare coated products with quality and texture and more marketability in this growing market.

Lactic acid bacteria (LAB) are the main and natural components of the microflora of the digestive system. Identification of lactic acid bacteria and their use in the food industry is very important.

In order to isolate natural lactic acid bacteria, samples of local yogurt and traditional tarkhineh were collected from different regions of Lorestan province, with respect to suitable geographical distances and different weather conditions. After separating gram-positive and catalase-negative bacteria, 20 lactic acid bacteria were selected and then using specific primers, the 16SrDNA gene was amplified and after alignment and comparison with the NCBI database, the type of bacteria was determined. In order to estimate the genetic diversity between the studied bacteria using the RAPD marker, 4 primers were used. Finally, a phylogenetic tree was made between the studied bacteria.

Based on the antibiogram test, it was found that all the studied bacteria were resistant to kanamycin and amikacin antibiotics and sensitive to gentamicin, vancomycin and tetracycline antibiotics. Bacteria isolated from tarkhineh with 97% similarity and bacteria isolated from yogurt with 89% similarity were placed in the same group. Two bacterial strains isolated from yogurt were 94% similar to L.rhamnosus bacteria. In relation to the two bacterial strains isolated from tarkhineh sample, the results showed that these two bacteria were 98% similar to L. pentosus bacteria. Based on the results of grouping by RAPD-PCR marker, the studied bacteria formed 6 groups with a similarity coefficient of 57%, and one genotype alone formed one group. Regarding the geographical distances and the grouping obtained, the bacteria samples isolated from the traditional products of similar geographical areas were placed in close groups.

The results generally showed that the use of genetic markers can be very effective in identifying the species and strains of lactic acid bacteria in dairy and fermented products.

Using food coatings containing essential oils with antioxidant and antibacterial properties helps to increase the shelf-life of meat products. This study investigated the effect of chitosan coating with different concentrations of Barijah essential oil (0.25, 0.5, 1, and 2%) on the quality of chicken breast during 12 days of cold storage.

First, the antibacterial properties of Barijah essential oil were measured, and then after coating the chicken breasts, the qualitative properties namely color, bacteriological, and general acceptance characteristics were evaluated.

The results showed Barijah essence was more effective on Bacillus cereus bacteria than Escherichia coli (p<0.05). Coating the samples significantly improved the moisture and pH characteristics of chicken breast (p<0.05). The coating slowed down lipid oxidation and the formation of volatile nitrogen compounds in treatment (p<0.05). It also caused the tissue stiffness of the samples to be maintained (p<0.05). The color index showed that the use of coatings caused a decrease in the L* and a* values while the b* value increased (p<0.05). Microbial spoilage in the coated samples was significantly reduced as compared to the control sample (p<0.05). Samples containing 2% Barijah essence had better results than other treatments in all tests (p<0.05).  The acceptability of the treatment containing 1 and 2% Barig essence was the same and higher than other treatments (p<0.05).

The results showed that using chitosan with in essential oil of Barijah as a natural preservative increases the shelf life of meat products.

Nowadays, due to consumers' interest in fresh fish over frozen fish, the importance of keeping and supplying fresh fish is increasing day by day.

In this study, the effect of edible bioactive coating based on chia seed gum and nanoemulsion of ginger essential oil on the shelf life of rainbow salmon fillet during 12 days of storage in the refrigerator was investigated. In order to carry out this aim, fresh salmon fillets were prepared with four different gelatin solutions with different percentages from 2 to 15% of and then the fillets were stored in a refrigerator. In order to check the performance of this coating, microbial tests consisting of total microbial count, measurement of free fatty acids based on oleic acid, measurement of total volatile bases (TVN) and pH were periodically performed for all samples on days 1, 6, and 12.

According to Duncan's test, the results show that in the control sample, the microbial count is significantly (P<0/05) higher than the other samples, and also the microbial count tests show that on the 12th day, as compared to the 6th day and 6th day as compared to 1st day, there were significant increases (P<0/05). The acidity of extracted fat on the 12th day increased significantly (P<0/05) as compared to the first and sixth days.

In general, the results of this research indicated that these compounds can be used to increase the shelf life of rainbow salmon.