فصلنامه پژوهش و نوآوری در علوم و صنایع غذایی
سال یازدهم شماره 1 (بهار 1401)

Aerated dessert is a type of dessert based on the foam system, in which the presence of air in these desserts changes the rheological, sensory, and appearance characteristics. The aim of this study was optimization of aerated dessert using response surface methodology (RSM) and evaluate its rheological properties as a function of whey protein concentrate (2, 5 and 8%), xanthan gum (0.1, 0.25 and 0.4%) and whipping time (2, 5 and 8 min). The results showed that increasing protein and whipping time decreased density and increased overrun. Elevation of the xanthan gum concentration increased the density and decreased overrun. Optimal conditions for the production of aerated dessert foam with the lowest density and the highest overrun was determined in the concentration of xanthan gum 0.1% (low level), whey protein concentrate 8% (high level) and whipping time 8 min (High level). Power low model was the best model to describe flow behavior of the aerated dessert with high R2 (R2>0.99) and low RMSE (0.01). It was determined that with increasing the whey protein concentrate and xanthan gum decreased the flow behavior index and increased coefficient of consistency (P<0.05). Also, increasing the whey protein concentrate, xanthan gum and whipping time increased hardness, adhesiveness and consistency coefficient. The production of aerated desserts, in addition to producing a new product; increases the power of consumer choice and the profitability of the producer and can be an effective contribution to the growth of the industrial economy.

Decrease in nitrosamine and optimal smell and flavour gives credit to such meat products as fermented sausages for their considerable optimal storage period and better nutritional values. Replacing red meat with fish and using replacer fat and probiotics in such products have played a great role in the production of such a highly functional food. Therefore, the focus of this study is mainly on the production of fermented trout sausages applying Lactobacillus rhamnosus and Lactobacillus plantarum, substituting part of its fat with inulin while examining the physicochemical, textural, dietary, and sensory properties. The results showed that samples containing inulin lost less moisture over time (less than 4%). The fat content of the samples did not differ significantly over time and was almost the same. However, the pH of the samples containing probiotics decreased more than the control sample and reached about 4.6-4.8. Inulin content samples caused a marked decline in lightness and an increase in redness. Meanwhile, probiotic presence has caused more declines in lightness intensity in samples. Inulin content samples show more hardness as compared to high fat samples and the probiotics present after pH decline to isoelectric point caused an increase in intensity and hardness of protein fibers. Simultaneously, along with an increase in fat, cohesiveness increased. Nitrosamine content in probiotic samples was lower than the one in test sample much as there was an increase seen in all samples. Despite a little more odour being present, sensory analysis was in favour of the test samples. Other samples demonstrated little difference in sensory evaluation.

In recent years, the application of spore-forming bacteria in probiotic food supplements and medicine have become more interesting due to their stability in stressful condition of production line and gut environment. In the current study, the resistance of Bacillus coagulans and Bacillus subtilis in response to heat stress and simulated gastrointestinal tract was investigated. Moreover, the aggregation and hydrophobicity of cell surface of these strains were evaluated. The results showed a survival rate of more than 80% for both species after enduring heat stress and undergoing simulated gastrointestinal conditions. In addition, Bacillus coagulans showed a higher autoaggregation and coaggregation ability compared to Bacillus subtilis. In addition, both probiotic species presented a high tendency toward adhering to the hydrocarbon solvents like chloroform and ethyl acetate. This study was a continuation of previous studies conducted with the aim of developing and optimizing functional edible coating for the production of probiotic rock candy (Nabat) using spore-forming probiotic bacillus, to ensure the survival and effectiveness of the strains.

In this study, the crystallization behavior of beeswax in grape seed oil in a wide range of cooling rates of 0.04, 0.08, 0.16, 0.33 and 0.66 (°C/min), from 85 to 25 °C and wax concentrations of 10, 15 and 20% were examined. Thermal behavior characteristics, texture, color and the crystal shapes of the samples were evaluated. The results showed that with increasing the percentage of wax in oleogel, the onset and melting temperatures increased in different treatments, so that the greatest increase was shown in the cooling rate of 0.16 °C/min. Temperatures of 45.90±0.46 and 46.8±0.30 for 10 wax concentration up to 62.70±0.2 and 65.80±0.17 for 20% wax concentration for onset and melting temperatures, respectively were measured. With increasing wax concentration, the factors of stiffness and adhesiveness also increased and this increase was more evident in the cooling rate of 0.66 °C/min, so that the stiffness and adhesiveness parameters increased the most at concentrations of 10% to 20%, respectively. Also, with slow cooling rate, samples with larger crystals were obtained. Color evaluation revealed that with increasing wax concentration, all color parameters except parameter a*, which did not show a significant difference, increased in all cooling rate treatments. The fat crystal engineering approach followed here offers the prospect of obtaining stronger structures at oleogelator concentrations and creating oleogel with desirable properties.

At present, cereal bran is offered in our country without any processing to remove anti-nutritional compounds which can have adverse effects on consumers health. In this study, the effects of different conditions (power and time) of microwave treatment on the moisture content, anti-nutritional compounds (phytic acid and oxalic acid) and shelf life of barley, oat, and rice bran were evaluated. The samples were treated with microwave power of 2, 4, 6, 8 and 10 kW for 15, 30, 60, 90 and 120 s. The most optimum treatment to reduce moisture for barley, oat, and Iranian rice bran was 8 kW for 120 s. During the treatment at 8 and 10 kW microwave power for 120 s, around 50% loss in phytate and oxalate content was observed. There was no statistically significant difference between the results obtained for 8 and 10 kW radiation power. Therefore, treatment at 8 kW for 120 s to reduce phytate and oxalate in brans was identified as the optimal treatment. During the 28-day storage period under accelerated conditions, no statistically significant difference was observed between the moisture content and the percentage of free fatty acids in the treated samples with power of 8 and 10 kW. The results of the present study showed that treatment with 8 kW microwave power for 120 s for barley and rice brans and 10 kW for oat bran significantly reduced the amount of moisture, anti-nutritional factors of phytic acid and oxalic acid in all three bran samples and also reduced the amount of moisture, reduced lipase activity and production of free fatty acid during the 28-day accelerated storage period.

The aim of this study was to evaluate and predict changes in total viable count (TVC), Pseudomonas, Psychrotroph, Enterobacteriaceae, Lactic Acid bacteria and chemical parameters including volatile nitrogen bases (TVB-N) and malondialdehyde (MDA) in cooking silver carp burger at 45, 55, 65, 75 and 85 °C using artificial neural network. The cooking time was 20 and 30 min and the storage was 18 days. Cooking at 55 °C for 30 min had no effect on inactivating other groups, but it did affect Pseudomonas. Cooking at 65 °C for 20 min controlled Psychotrophs and Enterobacteriaceae and had no effect on other groups. The amount of Pseudomonas during cooking time of 20 min at 45 and 55 °C and Lactobacillus during cooking time of 20 min at 45 °C were not within the standard bacterial load and the results showed that fish burgers could be consumed in other treatments until the end of the storage period, except in these treatments. At both cooking times, the cooking temperature of 85 °C inactivated Pseudomonas, Enterobacteriaceae and Lactic Acid bacteria. Temperature had the most and time had the least effect on the model proposed for MDA. The burgers were within range of TVB-N during storage. By increasing the storage time, the color index L* was increasing and the color of the burgers tended to be white. It can be said that the neural network (MLP) results are reliable and can be used to reduce the cost of experiments in the production industry of burger.

Arcobacter butzelri, is the most common genus of the Campylobacteriaceae family, known as an emerging zoonotic pathogen. The aim of this study was to isolate, identify and determine the antimicrobial susceptibility of Arcobacter butzelri strains to antibiotics used in the treatment of infectious diseases in humans and animals. Therefore, 297 samples of chicken carcasses were collected in slaughterhouses of Tonekabon city. Suspected colonies were isolated and identified using biochemical test and polymerase chain reaction (PCR) technique was used to confirm the isolates. The pattern of antibiotic resistance of Arcobacter Butzleri to 16 antibiotics was determined by disk diffusion method and the minimum inhibitory concentration of the strains to tetracycline, erythromycin and gentamicin was determined by Broth Macrodilution (Tube) method. All of the 36 strains which were isolated and identified were resistant to penicillin 100%, ampicillin 100%, oxacillin 100% and also to resistance to trimethoprim/sulfamethoxazole 94.4%, ciprofloxacin 94.4%, nalidixic acid 91.7%, azithromycin 91.7% and amoxicillin 80.6% were evaluated. Of the 36 isolates tested, all isolates were sensitive to gentamicin 100%. 72% of strains had MIC≥128 (g/mL) and MBC≥256 (µg/mL) for tetracycline antibiotics. There were also 10 MDR strains (27.77%) and 24 XDR strains (66.66%). The findings indicate the presence of Arcobacter butzelri in chicken carcasses and the high prevalence of antimicrobial resistance to various antibiotics in this area.

Natural antimicrobial and antioxidant compounds in extracts and essential oils of plant can be used in the edible coatings for packaging of food product. The aim of this study was to investigate the effect of edible chitosan containing Froriepia subpinnata extract on storage time of Nile tilapia (Oreochromis niloticus) fille After preparation of fresh fish, except the control group (first treatment), fish fillets were coated with 2% chitosan solution (second treatment), 2% chitosan solution and 1% F. subpinnata extract (third treatment) and 2% chitosan solution and 2% F. subpinnata extract (fourth treatment) then kept at refrigerator temperature for 21 days. At the beginning of the experiment and at 7th, 14th and 21st days, chemical indexes (pH, total volatile nitrogen bases and thiobarbituric acid), microbial count (mesophilic bacteria, enterobacteriaceae, psychrophile bacteria and mold and yeast) and sensory evaluation of samples were analyzed. Generally, coated treatments showed better quality than the control group in terms of investigated microbial and chemical indexes. Also, the treatment coated with chitosan and 2% of F. subpinnata extract showed significant differences (P˂0.05) compared to the control group in terms of studied indexes until 21st day, and was known the best treatment beside the other treatments. Coating of tilapia fillets with chitosan containing 2% of F. subpinnata extract improves chemical and microbial indexes and increases their shelf life up to 14 days in comparison with control.