Mycoflora and ochratoxin a control in wheat grain using natural extracts obtained from wine industry by-products

Characteristic Structures of Different Stilbenes Distinguish the Impact on Ochratoxin A Biosynthesis Intermediate Pathway and Metabolites of Aspergillus carbonarius

In this paper, we accurately pinpointed the inhibition sites of ochratoxin A (OTA) synthesis pathway in Aspergillus carbonarius acted by stilbenes from the perspective of oxidative stress and comprehensively explored the relationship between the physical and chemical properties of natural polyphenolic substances and their biochemical properties of antitoxin. To facilitate the application of ultra-high-performance liquid chromatography and triple quadrupole mass spectrometry for real-time tracking of pathway intermediate metabolite content, the synergistic effect of Cu²⁺-stilbenes self-assembled carriers was utilized. Cu²⁺ increased the generation of reactive oxygen species to accumulate mycotoxin content, while stilbenes had the inhibitory effect. The impact of the m-methoxy structure of pterostilbene on A. carbonarius was found to be superior to that of resorcinol and catechol. The m-methoxy structure of pterostilbene acted on the key regulator Yap1, downregulated the expression of antioxidant enzymes, and accurately inhibited the halogenation step of the OTA synthesis pathway, thus accumulating the content of OTA precursors. This provided a theoretical basis for the extensive and efficient application of a wide range of natural polyphenolic substances for postharvest disease control and quality assurance of grape products.

Exploring the Potential of Grape Pomace Extract to Inhibit Thermo-Oxidative Degradation of Sunflower Oil: From Routine Tests to ATR-FTIR Spectroscopy

Exploring new sources of natural antioxidants is of great interest to edible oil producers, in line with the toxicological problems generated by the use of synthetic antioxidants. This study assesses the potential of lyophilized Pinot Noir grape pomace extract (GPE) to enhance the sunflower oil stability against thermo-oxidative damage compared to BHT during a prolonged exposure to convective heat at 185 °C. Oil thermo-oxidation was monitored based on specific indices such as peroxide value (PV), para-anisidine value (p-AV), inhibition of oil oxidation (IO), total oxidation (TOTOX) value, conjugated dienes and trienes (CDs, CTs), but also by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), where absorbance ratios A 3009 cm^-1/A 2922 cm^-1 (RI), A 3009 cm^-1/A 2853 cm^-1 (RII), A 3009 cm^-1/A 1744 cm^-1 (RIII) and RIV = A 1744 cm^-1/A 2922 cm^-1 (RIV) were investigated. GPE showed a significant inhibitory effect on oil thermo-oxidation and this response was concentration-dependent. Substantial decreases in the investigated indices, compared to the control without added antioxidants, were obtained after 4 h and 8 h of heat exposure of the 800 ppm GPE sample: PV (47%; 42%), p-AV (38%; 33%), IO (54%; 46%), TOTOX (41%; 37%), CDs (46%; 39%), CTs (44%; 29%). Oil exposure to heat resulted in changes in RI-RIV attributed to the reduction in the degree of unsaturation, in response to primary and secondary lipid oxidation. FTIR spectroscopy can be used to differentiate untreated and heat-treated oils based on the absorbance ratios. An inhibitory effect close to that of BHT was achieved by 500 ppm GPE, while a dose of 800 ppm provided greater protection against thermo-oxidation. Our results promote GPE as a natural additive to limit the thermo-oxidative damage of plant oils.

Study on the Sustainability Potential of Thyme, Oregano, and Coriander Essential Oils Used as Vapours for Antifungal Protection of Wheat and Wheat Products

This study aims to highlight the antifungal, antimicotoxigenic potential and phytotoxic effect of three essential oils (EOs) of Origanum vulgare (OEO), Thymus vulgaris (TEO), and Coriandrum sativum (CEO) on wheat storage, but also the impact of EOs treatment on the sensory properties of bakery products obtained from the wheat seeds. The chemical composition of EOs was determined using GC-MS analysis; the fungal load was evaluated using the direct plating technique, while mycotoxin analyses were conducted using enzyme-linked immunosorbent assay (ELISA). A selective antifungal effect has been highlighted in terms of the action of EOs vapours. OEO and TEO are inhibited Alternaria, Fusarium and Drechslera, while Saccharomyces and Cladosporium have proven to be the most tolerant fungi. Drechslera is the most sensitive, the effect of all EOs being a fungicidal one. However, the fungicidal effect proved present in all EOs applied as vapours with values ranging between 0.2–0.4%. Regarding the phytotoxic effect of EOs vapours on the germination of the seeds, TEO and OEO had an inhibitory effect, especially at 0.4%. The effect is cumulative over time. The EOs inhibited deoxynivalenol (DON) occurrence; the maximum percentage of inhibition was obtained after 21 days of vapours exposure, being more effective in the case of 0.2%. EOs vapours treatment does not affect the quality of bread obtained from treated wheat seeds from a sensory point of view.

Strategies to Improve the Thermo-Oxidative Stability of Sunflower Oil by Exploiting the Antioxidant Potential of Blueberries Processing Byproducts

This research was conducted in order to establish the effectiveness of two freeze-dried extracts obtained from blueberry processing byproducts resulting from juice manufacturing compared to butylated hydroxytoluene (BHT) in delaying the lipid oxidation of sunflower oil subjected to high-temperature convective heating at 180 °C up to 12 h under simulated frying conditions. The fruits were harvested from spontaneous flora of two regions of Romania, Arieseni (Alba County) and Paltinis (Sibiu County) and the blueberry byproducts extracts (BBE) were noted according to the origin place as ABBE and PBBE. The progress of lipid thermo-oxidation was investigated in terms of peroxide value (PV), p-anisidine value (p-AV), the response of TBA-malondialdehyde interactions assessed by thiobarbituric acid (TBA) method, the total oxidation (TOTOX) value and inhibition of oil oxidation (IO). The recorded data highlighted that BBE exhibit a high inhibitory response on lipid thermo-oxidation. The inhibitory effect was concentration-dependent, thus, the degree of lipid oxidation was in reverse related to the BBE dose. The exposure of the oil samples supplemented with 800 ppm BBE (ABBE, PBBE) to a high-temperature heating for 12 h led to a significant decrease of the assessed indices compared to additives-free sunflower oil sample as follows: PV (46%; 45%), p-AV (21%; 17%), TOTOX (27%; 24%), TBA value (25%; 11%). Regarding the impact of the origin on the potential of BBE to inhibit the lipid oxidative degradation, it was noted that ABBE derived from blueberries grown in a region with a milder climate with moderate precipitations and higher temperatures showed a stronger inhibitory effect on lipid thermo-oxidation than PBBE. A moderate level of 500 ppm BBE inhibited the lipid oxidation similar to 200 ppm BHT. The reported results reveal that BBE represent efficient natural antioxidants that could be successfully applied to improve the thermo-oxidative stability of sunflower oil used in various high-temperature food applications.

Grape Pomace as a Promising Antimicrobial Alternative in Feed: A Critical Review

Antimicrobial resistance is among the most urgent global challenges facing sustainable animal production systems. The use of antibiotics as growth promoters and for infectious disease prevention in intensive animal-farming practices has translated into the selection and spread of antimicrobial resistance genes in an unprecedented fashion. Several multi-resistant bacterial strains have been isolated from food-producing animals, thus constituting an alarming food-safety issue. Many industrial byproducts with potential antimicrobial properties are currently being investigated to identify empirical and affordable solutions/alternatives that can potentially be used in feed for animals. Grape pomace is among such byproducts that gained the attention as a result of its low cost, abundance, and, most importantly, its bioactive and antibacterial properties. This review discusses the recently reported studies with regard to exploring the use of grape pomace (and its extracts) in animal production to control pathogens, along with the promotion of beneficial bacterial species in the gut to ultimately alleviate antibacterial resistance. The review further summarizes realistic expectations connected with grape pomace usage and lists the still-to-be-addressed concerns about its application in animal agriculture.

Resveratrol and Related Stilbenoids, Nutraceutical/Dietary Complements with Health-Promoting Actions: Industrial Production, Safety, and the Search for Mode of Action

This paper reviews the potential of stilbenoids as nutraceuticals. Stilbenoid compounds in wine are considered key factors in health-promoting benefits. Resveratrol and resveratrol-related compounds are found in a large diversity of vegetal products. The stilbene composition varies from wine to wine and from one season to another. Therefore, the article also reviews how food science and technology and wine industry may help in providing wines and/or food supplements with efficacious concentrations of stilbenes. The review also presents results from clinical trials and those derived from genomic/transcriptomic studies. The most studied stilbenoid, resveratrol, is a very safe compound. On the other hand, the potential benefits of stilbene intake are multiple and are apparently due to downregulation more than upregulation of gene expression. The field may take advantage from identifying the mechanism of action(s) and from providing useful data to show evidence for specific health benefits in a given tissue or for combating a given disease.

Modulation of the intestinal microbiota is associated with lower plasma cholesterol and weight gain in hamsters fed chardonnay grape seed flour

The relationship between the intestinal microbiota and the hypocholesterolemic and antiobesity effects of whole grape seed flour from white and red winemaking was evaluated. Male Golden Syrian hamsters were fed a high-fat (HF) control diet or a HF diet supplemented with 10% partially defatted grape seed flours from either Chardonnay (ChrSd) or Cabernet Sauvignon (CabSd) grapes for 3 weeks. The numbers of total bacteria and relative abundances of Bifidobacterium spp., Lactobacillus spp., and Firmicutes in feces were significantly lower, while the relative abundance of Bacteroides fragilis was greater than the control from feeding the ChrSd diet. The ratio of Firmicutes/Bacteroidetes (F/B) was lower in the ChrSd diet. There were significantly positive correlations between Lactobacillus spp., ratio of F/B, and plasma total- and LDL-cholesterol and liver weight. The reduction of Lactobacillus spp. by the ChrSd diet was accompanied by inhibition of Farnesoid X receptor (FXR) signaling in the intestine as expression of intestinal fibrablast growth factor (FGF)15, positively regulated by FXR, was decreased. Expression of CYP7A1, negatively regulated by FGF15, was up-regulated in the liver, which indicates that alteration of the intestinal microbiota may regulate bile acid and lipid metabolism. These findings suggest that beneficial health effects of Chardonnay grape seed flour on HF-induced metabolic disease relate in part to modulation of intestinal microbiota and their metabolic processes.

Assessment of inhibitory potential of essential oils on natural mycoflora and Fusarium mycotoxins production in wheat

Background

In the last years essential oils from different plants were used in the prevention of fungi and mycotoxins accumulation in cereals. The most attractive aspect derived from using of essential oils as seed grains protectants is due to their non-toxicity. This study was focused on assessment the inhibitory effect of some essential oils: Melissa officinalis (O1), Salvia officinalis (O2), Coriandrum sativum (O3), Thymus vulgaris (O4) Mentha piperita (O5) and Cinnamomum zeylanicum (O6) against natural mycoflora and Fusarium mycotoxins production correlated with their antioxidants properties.

Results

All essential oils showed inhibitory effect on fungal contamination of wheat seeds. This ability was dose-dependent. The highest inhibitory effect on Fusarium and Aspergillus fungi was recorded after 5 days of treatment. Fungi such as yeast (Pichia, Saccharomyces and Hyphopichia) were predominantly on seeds mycoflora after 22 days. Each treatment had a selective inhibitory effect on frequency of fungus genera. After 5 days of treatment the most fungicidal effect was recorder for O4, followed by O1. In terms of essential oils effect on mycotoxins development, the best control on fumonisins (FUMO) production was recorded for O6. The antioxidant properties of essential oils decreased in order: O4 > O1 > O6 > O5 > O2 > O3. Also, our data suggested that there is a significant negative correlation between antioxidant properties and seed contamination index (SCI), but there was not recorded a good correlation between antioxidant properties and FUMO content.

Conclusions

Based on proven antifungal and antimycotoxin effects as well as their antioxidant properties, the essential oils could be recommended as natural preservatives for stored cereals. The highest inhibition of fungal growth was noted after 5 days of treatment and decreased after 22 days.

Enhancing oxidative stability of sunflower oil during convective and microwave heating using grape seed extract

This study was performed to investigate the effectiveness of grape seed extract (GSE) compared to butylated hydroxytoluene (BHT) on retarding lipid oxidation of sunflower oil subjected to convection and microwave heating up to 240 min under simulated frying conditions. The progress of lipid oxidation was assessed in terms of peroxide value (PV), p-anisidine value (p-AV), conjugated dienes and trienes (CD, CT), inhibition of oil oxidation (IO) and TOTOX value. In addition, total phenolic content (TP) was evaluated in samples before and after heating in order to assess the changes in these compounds relative to the extent of lipid oxidation. The results of this study highlight that GSE showed a significantly inhibitory effect on lipid oxidation during both treatments, although to a different extent. This ability was dose-dependent; therefore, the extent of lipid oxidation was inversely related to GSE level. Convective heating, respective microwave exposure for 240 min of samples supplemented by GSE to a level of 1000 ppm, resulted in significant decreases of investigated indices relative to the control values as follows: PV (48%; 30%), p-AV (29%; 40%), CD (45%; 30%), CT (41%; 36%), TOTOX (35%; 37%). GSE to a level of 600-800 ppm inhibited the lipid oxidation in a similar manner to BHT. These results suggested that GSE can be used as a potential natural extract for improving oxidative stability of sunflower oil during thermal applications.