Assessing synergistic effect of Jerusalem Artichoke juice and antioxidant compounds on enhanced viability and persistence of Bifidobacterium species, palatability, and shelf life.

Commercial vegetable and fruit juices with probiotics are new functional type of beverages; however, limitations including persistence and impact of probiotic bacteria on palatability and shelf life may prevent their industrial development. This study evaluated the effect of antioxidant compounds (ascorbic acid, astaxanthin, and ginseng) on viability and persistence of Bifidobacterium spp. in Jerusalem Artichoke (JA) juice; and determine the impact of these antioxidants on the sensory (color, texture, flavor, acidity) properties, free reducing sugar (inulin and fructose), and shelf life in the fortified JA juice. Overall, the JA juice fortified with ascorbic acid showed a significant impact on the rate of persistence of two targeted bifidobacterial strains from 1 to 28 days at 5°C. Both strains produced slight acidity in ascorbic acid fortified JA juice as compared to other tested samples. Similarly, the JA juice fortified with ascorbic acid showed a significantly high increase in the total number of bifidobacterial cells of both species, enhanced palatability, and shelf life as compared to astaxanthin and ginseng extract. The quadratic model indicated a strong association between ascorbic acid, ginseng extract, and astaxanthin with a bifidobacterial cell concentration in the fortified JA juices. The Box-Behnken design was considered a feasible analysis for describing fortified JA juice and the rate of viability and persistence of bifidobacteria during 28 days of storage at 5°C in all trials. In conclusion, JA juice fortified with ascorbic acid showed a significant impact on improving the cell viability and persistence of probiotic bacteria, enhanced palatability, and shelf life as compared to other compounds tested.

Effect of pulsed light treatment on enzymes and protein allergens associated with their structural changes: a review.

The pulsed light (PL) technique is used for food and surface decontamination widely. The sterilization effect of PL is well known and identified as the photo-chemical effect. Besides, PL is used to inactivate enzymes, reduce the immunoreactivity of proteins, and change protein function properties at a laboratory level. The current study aims to review the effect of PL on proteins by highlighting the differences between proteins in buffer solutions or food systems. Although PL is known as a non-thermal technique, most studies done on food systems, food temperature raised considerably. Therefore, PL inactivated many enzymes in buffer solution non-thermally, while mostly with a high increase in temperature of a food system. PL reduced food allergens several folds in some foods. However, immunoreactivity responses of some protein were increased after PL treatment. Also, the current study covers the conformational changes of proteins that occur because of PL treatment. Therefore, some techniques used to follow proteins structural changes such as polyacrylamide gel electrophoresis (SDS-PAGE), high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), etc. were defined. Studies reported that PL altered proteins structure differently. For example, some studies reported that PL degraded some proteins, while other studies suggested that PL aggregated proteins. Also, there were contrary results regarding α-helix and ß-sheet concentration for the treated proteins. In conclusion, some techniques, such as amino acid sequencing, specially when some small new fragments proteins appeared on SDS-PAGE, should be used to detect the effect of PL on proteins precisely.