Estamaran date vinegar: chemical and microbial dynamics during fermentation.

Vinegar is a fermented food produced by alcoholic and then acetic acid microbial metabolism. Date palm fruit (Phoenix dactylifera L.) is a valuable source for the production of vinegar. Microbial identification has a major role in the improvement and bio-management of the fermentation process of vinegar. Estamaran and Kabkab two varieties of date palm fruit were selected to study the fermentation process. A culture-dependent approach was used to study bacterial dynamics. 16 S rRNA gene was amplified by Polymerase Chain Reaction (PCR), also restriction enzyme analysis with HinfI and TaqI, and sequencing was done. Assessment of microbial flora of date palm fruit during fermentation showed that Fructobacillus tropaeoli, Bacillus sp., Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, and Weissella paramesenteroides existed in the first phase of fermentation. With fermentation progress, microbial diversity decreased so only one species remained. Komagataeibacter xylinus as an acid acetic producer was present in the third phase of fermentation. Based on chemical analysis, the concentration of reducing sugars decreased during fermentation. With decreasing pH, a simultaneous increase in acidity and total phenolic compounds occurred. The trend of changes during Estamaran fermentation was more severe and a vinegar with desirable properties was produced. Therefore, this date variety is recommended for the production of date vinegar.

Fortified cake with pomegranate seed powder as a functional product.

Pomegranate seed as a by-product of the pomegranate juice processing industry contains a range of valuable pharmaceutical and nutritional compounds. It's application as a food supplement leads to enhancement of the nutritional value and healthy properties of final products. In this research, various levels (2.5, 5, 7.5, and 10%) of pomegranate seed powder (PSP) were used in the cupcake formula and their effects on the physicochemical, sensorial, and microbial properties of the final product were evaluated during 28 days of storage at 4 °C. Adding PSP to the cupcake formula significantly increased the protein, fat, and fiber contents of the product (p < 0.05) but did not affect the oxidative stability of cupcakes during the storage time. The PSP increased the hardness of the cupcake. It was also effective in maintaining the moisture content of the product during the storage time. The results indicated that the specific volume, lightness, and yellowness of crust and crumb were decreased by increasing the level of PSP, while the redness of crumb was increased. Besides, the results of the sensory evaluation showed the addition of PSP up to 5% to cupcake formula did not have a significant negative effect on the sensory characteristics of the product. It could be concluded that the PSP could be used in cupcake formulation up to 5% as a flour replacement for nutritional and functional enrichment of cake without adverse effect on cake quality.

Physicochemical changes of barberry juice concentrated by liquid desiccant-assisted solar system and conventional methods during the evaporation process.

The preservation of the quality characteristics of fruit juices during the processing is one of the major challenges in the fruit juice industries. The high costs of fossil fuels and their environmental pollution increased the need to use of the renewable energies. In the present study, some quality characteristics of barberry juice were investigated during concentrating by the methods of liquid desiccant-assisted solar juice concentration system (LD-ASJCS) at the air flow rates of 0.006-0.014 kg/s, rotary vacuum evaporation system (RVES), and evaporation at atmospheric pressure (EAP). Although evaporation rate in LD-ASJCS increased by 25% with increasing of air flow rate from 0.006 to 0.014 kg/s, but it had negative effects on some quality properties of concentrated juices. The anthocyanins retention in the concentrated juices with different air flow rates of LD-ASJCS method were 16-28%. Reduction of the air flow rate resulted in a lower browning index and less variation of color indices (L*, a*, and b*). The a* values, browning index, and sensory attributes of the concentrated juices in the LD-ASJCS at the air flow rate of 0.006 kg/s were comparable to the concentrated juices by the RVES method. Although, RVES method compared to EAP and LD-ASJCS methods better improved the quality of barberry juice, but the LD-ASJCS method can be considered in fruit juice industries because of maintaining quality and sensory attributes, saving energy, and reducing environmental pollution. The mathematical modelling of physicochemical changes of LD-ASJCS concentrated juice showed that these variations are fitted with first-order and zero-order models.

Effects of a rotational UV-C irradiation system and packaging on the shelf life of fresh pistachio.

BACKGROUND: In this study, fresh pistachio was exposed to UV-C irradiation (2.1 and 4.5 kJ m-2 ) in a rotating cylindrical system with seven germicidal UV-C lamps and immediately packed in perforated and non-perforated polyethylene terephthalate (PET). The fruit were evaluated for weight loss, total phenolic content, enzyme activities, color indices (L*, a*, b* and browning index), and microbial counts during 35 days of storage at 4 °C. RESULTS: UV-C treatment caused a significant decrease (P < 0.05) in the weight loss of fresh pistachios compared to the control. The activity of catalase and peroxidase enzymes was significantly higher (P < 0.05) in irradiated samples packed in non-perforated PET in comparison to those of untreated samples. Irradiation did not inhibit the activity of polyphenol oxidase in treated samples, although a slight decrease in polyphenol oxidase activity was observed in irradiated samples compared to control. The fruit treated with 2.1 kJ m-2 of UV-C and the control packed in non-perforated PET were lighter (L*), redder (a*), and less yellow (b*) compared to 4.5 kJ m-2 treated samples. Furthermore, a dose of 4.5 kJ m-2 UV-C significantly decreased sensory attributes of fresh pistachios compared to the other irradiation level and control. CONCLUSION: UV-C irradiation at a dose of 2.1 kJ m-2 and packing in non-perforated PET are recommended for fresh pistachio preservation based on the physicochemical, microbial, and sensory parameters. © 2019 Society of Chemical Industry.