The current study aimed to evaluate the preservation of hummus packed in laminated pouches to extend its shelf life for a period of 35 d using a combined treatment of gamma irradiation and refrigerated storage. The effects of different irradiation doses (0, 0.1, 1.5 and 2.5 kGy) and refrigeration (4 °C) against microbial spoilage were investigated. Microbial criteria of total mesophilic aerobic counts, lactic acid bacterial counts, and yeasts and molds decreased significantly ( P ≤ 0.05) in a dose dependent manner. Furthermore, dose of 2.5 kGy decreased the lactic acid bacteria counts to undetectable levels for the first 10 d of storage. Although microbial load increased during 35 d of refrigerated storage, samples treated with doses of 1.5 and 2.5 kGy showed a good microbial quality that complies with microbial limits set by national and international authorities for ready to eat foods. Furthermore, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis and coliform bacteria were not detected in the irradiated samples as well as in the controls. It was observed that a dose ≥1.5 kGy combined with refrigerated storage at 4 °C could be used to extend the shelf life of hummus samples in laminated pouches up to 35 d.

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Simultaneous determination of water-soluble B vitamins is a troublesome analytical procedure since they have greatly variable structures and acid-base properties which imposed difficulties on eluting them in short time and selecting wavelength of detection. The aim of the present study was to develop a simple method that overcomes these difficulties. The method was successful in simultaneous determination of B1, B2, B3, B6, B9, and B12 in premix and fortified flour by extracting vitamins with 0.1% (w/v) of ascorbate and ethylene diamine tetra-acetic acid (EDTA) solution followed by eluting using gradient mobile phase consisting of 0.03% trifluoroacetic acid aqueous solution (pH 2.6) and acetonitrile on high performance liquid chromatography (HPLC) instrument coupled with diode array detector (DAD). Elution of vitamins was completed within 9.3 min, and the lowest values obtained for limit of quantification (LOQ) for B1, B2, B3, B6, B9, and B12 were 0.6, 0.2, 0.8, 0.3, 0.5, and 0.7 μg/mL, respectively, at four wavelengths of 361, 280, 265, and 210 nm. In general, variation of wavelength of detection in the range from 210 to 361 nm affects sensitivity but had a marginal effect on the linearity and LOQ of the developed method and its application for determining B vitamins in premix and fortified flour. The 210 nm wavelength exhibited the highest sensitivity though resulted in higher values of B vitamins in fortified flour with respect to 265, 280, and 361 nm. Noteworthy, determination of B2 and B12 in the premix at 361 nm had relatively high RSD values compared to the lower wavelengths. Thus, wavelengths in the range from 265 to 280 may be more favorable over 210 and 361 nm. The method reported in the present work does not require any sample cleanup/preconcentration steps, and chromatographic elution was achieved in 9.3 min without the need for ion-pairing reagents.

This study was conducted to investigate the effect of cobalt complexation on the spectral properties of anthocyanins (AC) extracted from black grape pomace (Black Magic) and the effect of complexation on the pH stability of AC during storage. Initially, cobalt acetate tetrahydrate aqueous solution was complexed with AC crude extract and diluted separately in buffer solutions with different pH (3.5, 4.5, 5.5, and 6.5). Afterward, spectral changes were determined spectrophotometrically. pH stability was investigated using the same buffer solutions and stored for 7 days in the dark at room temperature, and the absorbance of each solution was measured daily using a spectrophotometer. Results indicated that complexation caused similar hypsochromic and hyperchromic shifts in max at all pH values. With regard to pH stability, the degradation of complexed AC followed first-order reaction kinetics causing half-lives to increase up to 80-fold as compared with noncomplexed AC, which was due to the sharp decrease in K (per day), indicating an improved pH stability as compared with noncomplexed AC. Therefore, Co(II) could be used in the stabilization of grape AC for the coloration of a wide range of foods and food products at near-neutral pH environments considering the health benefits of grape AC and the maximum nontoxic dose of Co(II) salt.