Aya Samy Ewesys Khalil

The aqueous extraction of bioactive compounds from wild mushroom fruiting bodies, focusing on carbohydrates, has been systematically examined. This study includes three mushroom species common in the northern hemisphere: Suillus luteus, Tricholoma equestre, and Hydnum repandum. These species were selected for their potential as cost-effective sources of bioactive compounds. For each species, the optimization of liquid-to-solid (LS) ratio (50:1 v/w to 150:1 v/w), temperature (70–90 °C), and processing time (3 to 5 h) was conducted to determine optimal parameters for total carbohydrate content (TCC), while minimizing reducing sugars to favor higher molecular weight polysaccharides. The bioactive properties were explored and optimized based on the antioxidant properties of extracts. The data were compared with previous studies on commonly cultivated mushrooms, such as Agaricus bisporus. Results show that the high LS ratio has the most significant influence on TCC content, though optimal values for other parameters (temperature and time) vary by species. The optimal LS ratios were 150:1 for Suillus luteus, 149.89 for Tricholoma equestre, and 149.76 for Hydnum repandum. Temperature and duration varied among species, with Suillus luteus requiring 5 h at 89.92 °C, Tricholoma equestre needing 3.98 h at 70.07 °C, and Hydnum repandum requiring 3.00 h at 70.01 °C. A similar trend was observed in minimizing reducing sugars, confirming the high LS ratio may support extracting longer polysaccharide chains. Studies on antioxidant activity revealed that bioactive molecules in the extract are water-soluble molecules; however, the optimal values for antioxidant activity are strongly mushroom-species-dependent. The optimal conditions for enhancing antioxidant activity of aqueous extracts, measured by ABTS method, were: for Suillus luteus, an LS ratio of 123.68, 5 h, and 86.63 °C; for Tricholoma equestre, an LS ratio of 95.27, 4.05 h, and 73.87 °C; and for Hydnum repandum, an LS ratio of 50.01, 5 h, and 89.98 °C. The aqueous extraction method proved efficient for recovering bioactive polysaccharide fractions from wild mushrooms.

The optimization of extraction parameters, including the process time, temperature, and liquid-to-solid ratio, was conducted in order to obtain the polysaccharide-rich fraction from the lyophilized Agaricus bisporus fruiting body. The efficiency of extraction for polysaccharides and antioxidant activity was determined by analyzing the extracts for total carbohydrate content, the reducing sugars content, and the antioxidant activity employing DPPH, ABTS, and hydroxyl radical scavenging assays. The results showed that all parameters, except for the extraction time, impacted differently on the extraction efficiency of polysaccharides and antioxidant activity. The highest total carbohydrate content was observed at the longest process time, highest temperature, and a liquid-to-solid ratio of 118 mL/g. To minimize the reducing sugar level, a lower temperature is required, while the highest antioxidant activity requires a moderate temperature and the lowest liquid-to-solid ratio. The optimization of antioxidant activity by means of the DPPH and H₂O₂ method failed, which shows that the specific mechanism of polysaccharides as antioxidants needs further investigation. The aqueous extraction method demonstrated to be an efficient and simple approach to recover the potentially bioactive polysaccharide fractions from Agaricus bisporus that are also active as antioxidants.

Ohmic heating (OH) is an electrothermal technology used to inactivate enzyme and microbial activities. This work aimed to study the impact of Ohmic Heating Under Vacuum (OHUV) which compared to conventional heating (CH) as well as storage stability at 5°C and 25 °C on microbial safety, and nutritional quality. The evaluation parameters were pH, titratable acidity, TSS, lycopene, ascorbic acid, PME, HMF, and microbiological activity. The obtained results showed that tomato paste samples that were treated by OHUV are significantly superior to CH in terms of all physicochemical and microbiological characteristics, as well as being the least harmful during storage in both transparent and dark packages. The results showed the changes in ascorbic acid, lycopene, and HMF values that were treated by OHUV at 25 °C and filled in transparent package are most affected compared to other treated samples. On the other hand, tomato paste samples stored in dark packages at 5 °C performed significantly better than those subjected to CH under the same conditions and activated PME the most had higher ascorbic acid and lycopene and fewer changes in HMF during storage time for 90 days. OHUV found to be a good alternative treatment in the production of tomato paste.

The effect of fermentation by Saccharomyces cerevisiae on biological properties of cinnamon (Cinnamomum cassia) was investigated. The study demonstrated that the extract of S. cerevisiae-fermented cinnamon (S.C.FC) has antioxidants higher than non-fermented one. The optimum results for antioxidant yield were noted with 10⁷ CFU S. cerevisiae/10 g cinnamon and 70 mL of dH₂O at pH 6 and incubated for 3 d at 35 °C. Under optimum conditions, ABTS, DPPH, and H₂O₂ radical-scavenging activity increased by 43.8, 61.5, and 71.9%, respectively. Additionally, the total phenols and flavonoids in S.C.FC were increased by 81.3 and 415% compared by non-fermented one. The fermented cinnamon had antimicrobial activity against L. monocytogenes, S. aureus, E. coli, S. typhi, and C. albicans. Also, the anti-inflammatory properties were increased from 89 to 92% after fermentation. The lyophilized extract of S.C.FC showed positive effect against Huh7 cancer cells which decreased by 31% at the concentration of 700 µg/mL. According to HPLC analysis, p-hydroxybenzoic acid, gentisic acid, catechin, chlorogenic acid, caffeic acid, and syringic acid were increased by 116, 33.2, 59.6, 50.6, 1.6, and 16.9%, respectively. Our findings suggest the applicability of cinnamon fermentation using S. cerevisiae as a useful tool for processing functional foods to increase their antioxidant and anti-inflammatory content. Graphical Abstract