Mariana-Atena Poiana

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

BackgroundIn 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.ResultsAll 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.ConclusionsBased 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.

Tracking antioxidant properties and color changes in low-sugar bilberry jam as effect of processing, storage and pectin concentration

BackgroundRecently, an increased interest in the identification of valuable possibilities for preserving the antioxidant properties of products obtained by thermal processing of fruits rich in bioactive compounds can be noticed. In this regard, an extensive analysis is necessary in terms of thermal processed products behavior in relation to various factors. The purpose of the present study was to assess the effect which processing and storage at 20°C has on the antioxidant properties and color quality of low-sugar bilberry jam with different low-methoxyl pectin (LMP) concentrations.ResultsFor all measured parameters, it should be noted that thermal processing induced significant alterations reported to the values registered for fresh fruit. Most important losses due to thermal processing were recorded for total monomeric anthocyanins (TMA) (81-84%), followed by L-ascorbic acid (L-AsAc) content (53-58%), total phenolics (TP) content (42-51%) and FRAP (ferric reducing antioxidant power) values (36-47%). Moreover, depreciation of the investigated compounds occurred during storage at 20°C. Jam storage for 7 months resulted in severe losses in TMA content in the range 58-72% from the value recorded one day after processing. This coincided with marked increases in polymeric color percent of these products after 7 months of storage. Also, bilberry jam storage for 7 months resulted in a decrease in L-AsAc content of 40-53% from the value recorded one day after processing, 41-57% in TP content and 33-46% from the value recorded one day after processing for FRAP values. By decreasing of LMP concentration in the jam recipe from 1 to 0.3% there has been an increase in losses of investigated compounds.ConclusionOverall, the results indicated that bilberry jams can also represent a good source of antioxidant compounds, although compared to the fruit, important losses seem to occur. Practical application of this work is that this kind of information will be very useful in optimizing the jam processing technology and storage conditions, in order to improve the quality of these products.

The occurrence of mycotoxins in wheat from western Romania and histopathological impact as effect of feed intake

BackgroundThe goal of this study has been to evaluate the extent of mycotoxins contamination and their co-occurrence in wheat grain intended for animal feed. A total of 52 wheat samples were collected from the harvest of two consecutive years (2010, 2011) from two counties (Timis and Arad) located in Western Romania and the presence of ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZON) and fumonisins (FUMO) was determined by enzyme-linked immunosorbent assay (ELISA). In order to evaluate the toxicological impact of mycotoxins, naturally contaminated wheat samples were administered in rats feed for one month.ResultsThe mycotoxin with the highest incidence in wheat samples was DON due to agro-climatic conditions typical for the west part of Romania. DON was found in 73.08% of samples harvested in 2010 and the highest level of contamination was 3390 ppb. The incidence of DON in sample from 2011 was lower than those of 2010, with a frequency of occurrence of 19.23%. The occurrence of ZON was in the range 69.23–76.92%, with an average value of 187.74 ppb. The OTA content in wheat was below the maximum tolerable limit established by EU Commission regulation for feed legislation (250 ppb). For FUMO the lowest percentage of positive samples was registered (15.38% in wheat sample harvested in 2010 and 11.54% positive samples in 2011). With respect to the co-occurrence of Fusarium mycotoxins, the results proved that ZON was found as a co-contaminant together with DON, especially when climatic conditions for development of fungus are favorable (high air humidity). The differences recorded between investigated localities and their classifications according to the mycotoxin kind and year of harvest were carried out by principal components analysis (PCA). The histopathological and immunohistochemical evaluation performed by hematoxylin and eosin (HE) staining technique as well as by assessing the vascular endothelial growth factor (VEGF) revealed significant modification of kidney, liver and spleen cells in the case of DON and FUMO. In terms of toxicity induced by OTA and ZON it was highlighted mixed normal and necrotic areas in liver, while histological assessment revealed normal VEGF expression in kidneys.ConclusionsAlthough none of the analyzed samples exceeding the stipulated maximum limits for cereals used as feed, a high incidence of mycotoxins produced by Fusarium species have been recorded (DON and ZON) in wheat samples harvested in Western Romania. Also, histopathological evaluation revealed significant tissue lesions in liver and kidney of rats after one month of feeding with natural contaminated wheat.

Use of ATR-FTIR spectroscopy to detect the changes in extra virgin olive oil by adulteration with soybean oil and high temperature heat treatment

Abstract The structural changes induced in extra virgin olive oil (EVOO) by adulteration with soybean oil (SBO) and heat treatment at 185°C for 4 and 8 h were investigated using Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) spectroscopy. Our results revealed that the band around 3006 cm–1 recorded shifts versus the percentage of adulterant. The changes in the absorbance at 3006 cm−1 (A3006) and in the ratio of the maximum heights of the bands at 3006 and 2925 cm−1 (A3006/A2925) were used to evaluate the EVOO adulteration. The regression analysis of A3006 and A3006/A2925 versus the percentage of adulterant was used to calculate the detection limits of adulteration. The time course of spectral changes showed that the oil heating caused notable modifications in the intensity of the absorption bands and induced no shifts in their exact position. The most relevant changes were reflected by conjugation and cis-trans isomerisation of double bonds, the formation of epoxides and widening of the band in the C=O region due to formation of secondary oxidation products. This study highlights that ATR-FTIR spectroscopy may be a promising means to differentiate among pure and adulterated oils and to study the thermooxidative processes in oils undergoing thermal stress. Graphical Abstract

Mycoflora and Ochratoxin A Control in Wheat Grain Using Natural Extracts Obtained from Wine Industry By-Products

The aim of this study was to evaluate the effect of some natural extracts obtained from grape pomace (GPE) and grape seeds (GSE) as compared to a synthetic food, antioxidant-butylated hydroxytoluene (BHT), in order to control fungal population and ochratoxin A (OTA) production in naturally contaminated wheat. The results showed that the addition of these extracts was efficient with OTA content decreasing. On treatment with these extracts the loss of OTA content after 14 days was in the range 7.8–28.3% relative to the control sample, but increased up to 26.48–37% after 28 days. The highest loss in OTA content was recorded for treatment with GPE at the 500 ppm level. Regarding the fungal development, the obtained results show that the total fungal populations were significantly reduced by using natural extracts. The most efficient extract was GPE. Both BHT and GPE inhibit the growth of Penicillium verrrucosum, for all doses, but less with Aspergillus genera. GPE affects the growth of other types of moulds such as Rhizopus microsporus, Fusarium graminearum, Alternaria infectoria and Cladosporium herbarum. Our data suggested that GPE and GSE are able to provide fungicidal and fungistatic protection and to control the OTA accumulation in wheat, at least in a similar manner to BHT.

Investigation on Crude and High-Temperature Heated Coffee Oil by ATR-FTIR Spectroscopy along with Antioxidant and Antimicrobial Properties

The coffee oil has a promising potential to be used in food industry, but an efficient use, especially in products that required high-temperature heating, depends on its chemical composition and the changes induced by processing. Since there is little information on this topic, the aim of our study was to investigate the crude green and roasted coffee oil (GCO, RCO) and heated (HGCO, HRCO) for 1 h at 200°C, by Fourier Transform Infrared (FTIR) spectroscopy and in terms of antioxidant and antimicrobial properties. The results of FTIR spectroscopy revealed that no statistically significant differences (one-way ANOVA, p>0.05) in the oxidative status of GCO and RCO were found. The coffee oils heating induced significant spectral changes in the regions 3100–3600 cm–1, 2800–3050 cm–1 and 1680–1780 cm–1 proved by the differences in the absorbance ratios A 3009 cm−1/A 2922 cm−1, A 3009 cm−1/A 2853 cm−1, A 3009 cm−1/A 1744 cm−1, A 1744 cm−1/A 2922 cm−1. These alterations were related to the reduction of the unsaturation degree due to primary and secondary oxidation processes of the lipid fraction. The radical scavenging ability of oils investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealed that the IC50 value of GCO was significantly lower than of RCO (p<0.05). The IC50 values of crude coffee oils were lower than those of heated samples. The antioxidant activity of oils was attributed to both antioxidant compounds with free-radical scavenging capacity and to lipids oxidation products generated by heating. In the first 6 h of incubation, the inhibitory activity of crude oils against E. coli and E. faecalis was not significantly different to the control (p>0.05). Also, HGCO and HRCO showed significantly different inhibitory potential related to the control (p<0.05). The heating induced statistically significant decreases in the effectiveness of coffee oils against the tested bacteria. GCO proved to be the most effective among investigated coffee oils against the tested bacteria.

Synergistic Antifungal, Allelopatic and Anti-Proliferative Potential of Salvia officinalis L., and Thymus vulgaris L. Essential Oils

The current study aimed to investigate the chemical composition and the synergistic potential of two essential oils (EOs), as obtained from Salvia officinalis L. (SEO), and Thymus vulgaris L. (TEO). The antifungal potential was tested in vitro against Fusarium graminearum (Fg 06_17), the herbicidal effect was studied using weed seeds of Amaranthus retroflexus (ARET), Chenopodium album (CALB), Echinochloa crus-galli (EGAL), but also wheat seeds (WS) of the Lovrin variety and tomato seeds Saint-Pierre of the variety. The GC-MS profile highlights that the mains compounds identified in SEO were: caryophyllene (25.364%), camphene (14.139%), eucalyptol (13.902%), and β-pinene (11.230%), while in TEO, the predominant phytochemicals were: γ-terpinene (68.415%) and p-thymol (24.721%). The results indicated that the tested EOs alone as well as in combination have allelopathic effect against investigated seeds, while the synergistic effect of TEO and SEO in terms of fungal growth was demonstrated at a level of 0.06%. Thyme and sage EOs exhibited in vitro anti-proliferative activity on two melanoma cell lines, namely A375 human melanoma and B164A5 mouse melanoma alone, as well as in combination. SEO was most effective in terms of decreasing the cell viability of murine and human melanoma cell lines when compared to TEO.