Impact of post-harvest processing or thermal dehydration on physiochemical, nutritional and sensory quality of shiitake mushrooms.

Shiitake mushrooms are one of the most popular and highly consumed mushrooms worldwide both in fresh and dry forms. However, it rapidly starts losing its quality immediately after harvest which necessitates processing and/or proper storage before being distributed. However, the processes used for preserving other mushrooms (e.g., Agaricus) become unviable for shiitake due to its uniqueness (higher respiration rate, varied biochemicals, growth, etc.) which demands individual studies on shiitake. This review starts by listing the factors and their interdependence leading to a quality decline in shiitake after harvest. Understanding well about these factors, numerous post-harvest operations preserve shiitake as fresh form for a shorter period and as dried forms for a longer shelf-life. These processes also affect the intrinsic quality and nutrients of shiitake. This review comprehensively summarizes and discusses the effects of chemical processing (washing, fumigation, coating, and ozone), modified atmosphere packaging (including irradiation) on the quality of fresh shiitake while discussing their efficiency in extending their shelf-life by inhibiting microbial spoilage and deterioration in quality including texture, appearance, nutrients, and favor. It also reviews the impact of thermal dehydration on the quality of dried shiitake mushrooms, especially the acquired unique textural, nutritional, and aromatic properties along with their merits and limitations. Since shiitake are preferred to be low-cost consumer products, the applicability of freeze-drying and sophisticated novel methodologies, which prove to be expensive and/or complex, are discussed. The review also outlines the challenges and proposes the subsequent future directives, which either retains/enhances the desirable quality in shiitake mushrooms.

Anti-senescence effects of Rhodiola crenulate extracts on LO2 cells and bioactive compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhodiola crenulata (Rc) is a traditional herb, used in Tibetan medicine, has shown promise efficacy in physical performance improvement, work capacity enhancement, fatigue elimination, and altitude sickness prevention. Also, Rc exhibited therapeutic effects on aging-related diseases. However, relevant researches on Rc and their bioactive components are quite few and needs further investigation. AIM OF THE STUDY: The objective of this study was to understand the relationship between phytochemical profiles and their activities of Rc extracts. MATERIALS AND METHODS: Rc extracts prepared by solvents with various hydrophilicity (i.e. aqueous ethanol (70%, v/v), water, and ethyl acetate), and their chemical compositions and specific compounds were analyzed by chemical analysis method and ultra-performance liquid chromatography quadruple time-of-flight mass spectrometry (UPLC-QTOF-MS). The regulate effects of Rc extracts on senescence and antioxidant activity were evaluated using the models of LO2 cells and Caenorhabditis elegans. RESULTS: The 70% ethanol extracts exhibited better regulating effects on senescence via the assays of senescence -associated ß-galactosidase (SAßG) staining and lifespan, which was consistent with the higher antioxidant activities observed based on the results of antioxidant assays. A total of 14 phytochemicals have been identified in 70% ethanol extracts, whereas the other two extracts contained much fewer compounds in varieties. Phytochemical profile of water extract was similar to the first half (polar compounds, running time: 0-6 min) of 70% ethanol extract profile, while those of ethyl acetate extract was consistent with its second half (more nonpolar compounds, running time: 6-12 min). CONCLUSIONS: The 14 phytochemicals in Rc might exhibit additive or synergistic effects on senescence regulating and antioxidant activities, providing theoretical basis for daily administration of Rc.

Improvement effects of micronization on morphology, functional and nutritional attributes of stabilized rice bran.

Micronization affects physicochemical and functional properties of materials and hence might improve the quality of rice bran, following stabilization treatments. The micronization effects of stabilized rice bran via extrusion or radio frequency treatments on their morphology and functional properties, and releasable capability were investigated. Micronization reduced particle size, water binding capacity and swelling capacity of rice bran, and increased their whiteness, water solubility index, and nutrient releasability. However, no significant changes in oil binding capacity and thermal index after micronization were observed. Moreover, micronization could decrease the bulk density of rice bran stabilized by extrusion. The releasability of phenolics, flavonoids, γ-oryzanol, and minerals (K, Mg, Zn and Fe) from rice bran after micronization was improved based on in vitro digestion models. These findings suggested that micronization of rice bran following stabilization, especially extrusion treatment, could improve its functional and nutritional properties. The types of stabilization processing of rice bran, followed by micronization, should be considered practically for functional and nutritional properties.

Red Cabbage Rather Than Green Cabbage Increases Stress Resistance and Extends the Lifespan of Caenorhabditis elegans.

Many studies have demonstrated that cabbages possess various biological activities, and our previous studies confirmed that cyanidin-3-diglucoside-5-glucoside (CY3D5G), the major core of red cabbage anthocyanins, exhibited in vitro antioxidant activity. This study further investigated the protective effects of CY3D5G derivative from red cabbage juice (RCJ) on oxidative stress and lifespan in cells and Caenorhabditis elegans, green cabbage juice (GCJ) was used as control. RCJ rather than GCJ significantly improved cell viability and decreased lactate dehydrogenase release in H2O2-induced caco-2 cells. RCJ significantly increased survival during oxidative and heat stress and mean lifespan in C. elegans by 171.63% and 31.64%, and 28.16%, respectively, while GCJ treatment showed no significant effects (p < 0.05). These results might be attributed to significantly (p < 0.05) higher contents of total phenolics, ascorbic acid, glucosinolates, and anthocyanins in RCJ compared to those in GCJ. Additionally, both of them decreased autofluorescence and reproductive capacity, increased body length, but did not alter the intracellular ROS level. Prolonged lifespan by RCJ might require heat-shock transcription factor pathway, sirtuin signaling, and calmodulin kinase II pathway, independent of insulin/insulin-like growth factor-1 signaling pathway. RCJ showed promising antioxidant properties in caco-2 cells and C. elegans, which provided more information on the health benefits of cabbage.

Molecular interaction between pectin and catechin/procyanidin in simulative juice model: Insights from spectroscopic, morphology, and antioxidant activity.

The interactions between polysaccharides and phenolics in foods affect their physicochemical properties and bioactivity. Pectin and catechin/procyanidin present in plants ubiquitously and attracting more attentions for the potential health benefits. This work investigates the interactions between high methoxyl pectin and catechin/procyanidin in a simulative juice model using multiple microscopic and spectroscopic approaches and their influences on the antioxidant activity of phenolics were evaluated in the Caco-2 cells model. The results showed that pectin with either of phenolic compunds exhibited lower transmittance, zeta potential, viscosity, and larger particle size than it alone. The morphology of pectin complexes with either of phenolics under experimental conditions (pH = 3.5) was observed. The ΔH° (-6.821 kJ mol-1 ) and ΔS° (6.357×10-2  kJ mol-1 ) indicated that pectin interacts with procyanidin via electrostatic interaction, whereas hydrophobic interaction was the dominant drive force between pectin and catechin (ΔH° = 1.422 kJ mol-1 ; ΔS° = 13.048 × 10-2  kJ mol-1 ). The antioxidant activities of catechin/procyanidin decreased while binding with pectin based on indexes of glutathione peroxidase, total superoxide dismutase, total antioxidant capacity, and malondialdehyde. PRACTICAL APPLICATION: The findings of this work indicated that the physicochemical property of pectin and the antioxidant activity of catechin/procyanidin were influenced by the interactions between pectin and catechin/procyanidin in a simulative food system. This study provides insights into the molecular interactions between pectin and phenolics in a simulative food system.

Investigation of the potential direct and cross protection effects of sublethal injured Salmonella Typhimurium induced by radio frequency heating stress.

Many studies demonstrated that radio frequency (RF) was an effective pasteurization method for low-moisture foods (LMFs), and our previous study confirmed RF heating stress generated sublethal injured cells (SICs) of Salmonella enterica serovar Typhimurium (S. Typhimurium) in red pepper powder with initial aw ≥ 0.53. So this study investigated the potential direct protection and cross protection effects of the SICs of S. Typhimurium to multiple stresses, and analyzed fatty acid composition and cell morphology. Results showed that the SICs were repaired after incubating for 5 h, and there were no obvious direct and cross protection effects by exposing to different external stresses (heat, 15% ethanol, pH 3.0 acid buffer solution, 10% salt). According to the fatty acid composition analysis, no significant difference (p > 0.05) between the ratio of unsaturated to saturated fatty acids (UFA/SFA) was observed for SICs of S. Typhimurium and control cells, indicating the same membrane fluidity which can support the experimental results. This study investigated and confirmed there are no direct and cross protection effects for the SICs of S. Typhimurium induced by RF heating stress, and it would be helpful for deeply understand the response of pathogens under RF heating stress.

Antitumor, Antioxidant, and Nitrite Scavenging Effects of Chinese Water Chestnut (Eleocharis dulcis) Peel Flavonoids.

The preparation, quantification, and characterization of flavonoid compounds from Chinese water chestnut peel (CWCP) flavonoid extract and ethyl acetate fraction (EF), n-butanol fraction, and water fraction were studied. Among these, EF showed the maximum free radical levels (IC50 values of 0.36, 0.40, and 0.37 mg/mL for DPPH•, ABTS•+ , and •OH, respectively), nitrite scavenging effects (IC50 = 1.89 mg/mL), and A549 cell inhibitory activities (IC50 = 776.12 µg/mL) with the highest value of total flavonoid content (TFC, 421.32 mg/g). Moreover, the contents of 8 flavonoids in this fraction were quantified using high-performance liquid chromatography, and fisetin, diosmetin, luteolin, and tectorigenin were the 4 major flavonoids with levels of 31.66, 29.91, 13.69, and 12.41 mg/g, respectively. Luteolin produced a greater inhibition of human lung cancer A549 cells (IC50 = 59.60 µg/mL) than did fisetin, diosmetin, and tectorigenin. Flow cytometry revealed that the cellular mechanisms of luteolin inhibition of A549 cells were achieved via the induction of cell proliferation arrest at G1 phase and apoptosis/necrosis. Our findings suggest that flavonoids are closely associated with antitumor, antioxidant, and nitrite scavenging effects of CWCP.

Effect of single- and two-cycle high hydrostatic pressure treatments on water properties, physicochemical and microbial qualities of minimally processed squids (todarodes pacificus).

This study investigated the effect of single- and two-cycle high hydrostatic pressure (HHP) treatments on water properties, physicochemical, and microbial qualities of squids (Todarodes pacificus) during 4 °C storage for up to 10 d. Single-cycle treatments were applied at 200, 400, or 600 MPa for 20 min (S-200, S-400, and S-600), and two-cycle treatments consisted of two 10 min cycles at 200, 400, or 600 MPa, respectively (T-200, T-400, and T-600). HHP-treated samples had higher (P < 0.05) content of P2b (immobilized water) and P21 (myofibril water), but lower P22 (free water) than those of control. The single- and two-cycle HHP treatments at the same pressure level caused no significant difference in water state of squids. The two-cycle HHP treatment was more effective in controlling total volatile basic nitrogen, pH, and total plate counts (TPC) of squids during storage, in which TPC of S-600 and T-600 was 2.9 and 1.8 log CFU/g at 10 d, respectively, compared with 7.5 log CFU/g in control. HHP treatments delayed browning discoloration of the squids during storage, and the higher pressure level and two-cycle HHP were more effective. Water properties highly corresponded with color and texture indices of squids. This study demonstrated that the two-cycle HHP treatment was more effective in controlling microbial growth and quality deterioration while having similar impact on the physicochemical and water properties of squids in comparison with the single-cycle treatment, thus more desirable for extending shelf-life of fresh squids.

Assessment of radio frequency heating on composition, microstructure, flowability and rehydration characteristics of milk powder

Abstract Radio frequency heating (RFH) provides higher efficiency and more uniform heating zone compared with conventional method. The aim of present work is to evaluate the effect of RFH (at 90 °C for 5 or 10 min) on the changes in composition (protein oxidation and fat distribution), microstructure, flow characteristic and rehydration property of infant milk powder. The results indicate that the concentration of protein dityrosine was slightly enhanced, more free fat appeared on powder surfaces (> 50% increase), and porosity in powder matrix as tested by SEM was increased after RFH treatment. For powder flowability, raw sample had low cohesiveness (specific energy = 4.39 mJ/g), and RFH provided better flowability and decreased compressibility. Moreover, RFH had some negative impacts on wettability and solubility of powder particles with contact angle increase at least 5% and solubility decrease of 2%~4%, indicating worse rehydration abilities. Guggenheim-Anderson-de Boer (GAB) model was applied to fit moisture vapor sorption isotherms, and longer RFH duration leading to higher c values (about 63% increase at 10 min). In addition, the RFH initiated browning reaction as CIE a* values increased from -1.8 to -1.3.