Efficiency of acetic acid and formic acid as a catalyst in catalytical and mechanocatalytical pretreatment of barley straw

In this study, the potential of organic acids (formic acid, acetic acid) in a catalytical and mechanocatalytic conversion of lignocellulosic barley straw to valuable sugars is explored using sulfuric acid as a reference. Acid-catalyzed hydrolysis has been carried out with acid-impregnated samples as well as unmodified barley straw. In the mechanocatalytical approach, pretreatment consists of impregnation with the acid catalyst and mechanical treatment by ball milling following chemical hydrolysis. Straw samples and residues were analyzed by Fourier transform infrared spectrometry (FT-IR) whereas hydrolysate analysis was based on total reducing sugar (TRS) determination following the DNS method and capillary electrophoresis (CE) analysis. The results indicated that acetic acid and formic acid are rather mild acids yielding low TRS levels compared to the reference acid. Mechanocatalytical pretreatment slightly increased TRS yields, but not significantly. Strikingly, sulfuric acid showed an efficient conversion efficiency yielding almost 45% of TRS. Furthermore, this study provided evidence for the acetylation of straw components when acetic acid was used as catalyst. Alkali hydrolysis induced the de-esterification, but revealed no significant increase of TRS yields.     

The analysis of trans fatty acid profiles in deep frying palm oil and chicken fillets with an improved gas chromatography method

An improved gas chromatography method for the simultaneous separation of 52 fatty acids (FAs) has been developed. For both oleic acid and linoleic acid, a good resolution was achieved for their positional and geometrical (cis/trans) isomers. This method was validated to be precise, accurate and sensitive. With this method, the FAs profiles in palm oil and chicken fillets were analyzed. In general, small changes were observed in the composition of FAs and formation of trans isomers after 8 h frying at the temperature lower than 200 °C. However, with extreme deep-frying process, the thermal degradation and TFAs formation in frying oil increased in direct proportion to frying temperature and time. Moreover, the FAs composition of fried chicken fillets was found to be mostly in correspondence with that of the frying oil, which might be due to the oil absorption or interaction between the frying oils and frying materials.     

A reliable and sensitive time-resolved fluorescent immunochromatographic assay (TRFICA) for ochratoxin A in agro-products

Immunochromatographic assays (ICAs) are considered as a suitable diagnostic tool for the detection of mycotoxins. Mycotoxins and especially, ochratoxin A are analytes with more demanding sensitivity requirements. To enhance the sensitivity of current immunochromatographic assays for ochratoxin A (OTA), a novel sensitive ICA was developed in this study. In the assay, microspheres enclosing fluorescent europium (III) [Eu(III)] nanoparticles (EuNPs) were used as a label for OTA monoclonal antibody (OTA-mAb) conjugation. Accordingly, assay was called time-resolved fluorescent immunochromatographic assay (TRFICA). The test strip was composed of three parts: a sample pad, nitrocellulose membrane and an absorbent pad. As for detection, a proper concentration of conjugated microspheres was pipetted into the microtube and sample extract was added to it. Then the strip was inserted into the tube and the fluid flow along the strip. The TRFICA results were obtained in 8 min and read by a portable TRFICA strip reader. The established method allows quantitative determination of OTA with limit of detection as low as 1.0 μg kg⁻¹ in the samples. For validation, spiked samples including wheat, maize, soybean and rice were respectively assayed by TRFICA and a standard high performance liquid chromatography equipped with a fluorescence detector (HPLC-FLD), and good agreement of results was obtained between two methods.     

Current major degradation methods for aflatoxins: A review

BackgroundAflatoxins are strong cancerogenic compounds predominantly produced by certain strains of the Aspergillus genus. Due to their extreme stability in different conditions, it is very difficult to remove them completely in human diet and animal feeds. In this way aflatoxins are triggering numerous healthy problems (such as liver cancer) and thus becoming a huge burden to the hygiene system and food industry worldwide.Scope and approachTherefore, seeking for an effective technique to degrade aflatoxins to a threshold level has been a “hot-topic” among researchers. Traditional methods to detoxify aflatoxins include physical and chemical treatments, such as an extrusion cooking process and ammoniation, respectively. Meanwhile a bio-degradation by microorganisms gains its popularity due to its friendliness to both environment and body health. Natural phytochemicals (plant extracts) which have great capability to remove aflatoxins without causing any damage on human and animals come out as an improvement.Key findings and conclusionHowever, a fully and systematically discussion of the methods of detoxification for aflatoxins is still not available. Therefore, in the present review we briefly enumerate several traditional strategies, update newly methods, particularly the potential use of natural phytochemicals, and discuss some mechanisms during the detoxification period, summarizing merits and demerits of these methods. We suggest that this important information and our humble opinions could help researchers to understand the degradation of methods for aflatoxins.     

Genome-Wide Identification and Characterization of Soybean GmLOR Gene Family and Expression Analysis in Response to Abiotic Stresses

The LOR (LURP-one related) family genes encode proteins containing a conserved LOR domain. Several members of the LOR family genes are required for defense against Hyaloperonospora parasitica (Hpa) in Arabidopsis. However, there are few reports of LOR genes in response to abiotic stresses in plants. In this study, a genome-wide survey and expression levels in response to abiotic stresses of 36 LOR genes from Glycine max were conducted. The results indicated that the GmLOR gene family was divided into eight subgroups, distributed on 14 chromosomes. A majority of members contained three extremely conservative motifs. There were four pairs of tandem duplicated GmLORs and nineteen pairs of segmental duplicated genes identified, which led to the expansion of the number of GmLOR genes. The expansion patterns of the GmLOR family were mainly segmental duplication. A heatmap of soybean LOR family genes showed that 36 GmLOR genes exhibited various expression patterns in different tissues. The cis-acting elements in promoter regions of GmLORs include abiotic stress-responsive elements, such as dehydration-responsive elements and drought-inducible elements. Real-time quantitative PCR was used to detect the expression level of GmLOR genes, and most of them were expressed in the leaf or root except that GmLOR6 was induced by osmotic and salt stresses. Moreover, GmLOR4/10/14/19 were significantly upregulated after PEG and salt treatments, indicating important roles in the improvement of plant tolerance to abiotic stress. Overall, our study provides a foundation for future investigations of GmLOR gene functions in soybean.     

微波辅助酶解棉籽粕的条件优化及酶解产物功能性质研究

研究了微波辅助碱性蛋白酶和风味蛋白酶双酶酶解棉籽粕的工艺条件.通过单因素实验确定了碱性蛋白酶酶解的最佳工艺条件为:微波温度60℃,微波功率500 W,酶加量5％(以底物质量计),酶解时间15 min;风味蛋白酶酶解的最佳工艺条件为:微波温度60℃,微波功率600W,酶加量5％(以底物质量计),酶解时间15 min.参照单因素优化条件,对棉籽粕进行连续酶解,酶解液多肽含量为13.32 mg/mL.棉籽粕经过微波连续双酶酶解后,吸油性、起泡性、乳化性等功能性质得到改善.     

Construction of an impedimetric immunosensor for label-free detecting carbofuran residual in agricultural and environmental samples

In this paper, a label-free electrochemical impedance immunosensor for the detection of carbofuran was prepared by immobilizing l-cysteine on a gold electrode. The carbofuran antibodies were immobilized on the electrode by the using glutaraldehyde as a cross linker. The stepwise assembly of the electrode surface was confirmed by atomic force microscope (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimized conditions, a linear relationship between the resistance change and the logarithm value of carbofuran concentration was obtained in the carbofuran concentration range of 1.0 × 10⁻¹ – 1.0 × 10³ ng/mL, with a detection limit of 1.0 × 10⁻¹ ng/mL. The immunosensor performed good reproducibility and stability. Additionally, the proposed method can be applied for monitoring carbofuran residual in agricultural and environmental samples.     

Rapid detection of adulteration of cold pressed sesame oil adultered with hazelnut,canola, and sunflower oils using ATR-FTIR spectroscopy combined with chemometric

Sesame oil is one of the most valuable oil due to its bioactive properties, unique taste, odor, and flavor. Therefore, consumers tend to consume and willing to pay a higher price for sesame oil due to increasing awareness of consuming healthier and better food. However, sesame oil is subjected to adulteration risks with lower price vegetable oils which impairs consumer rights and human health. In this study, we purposed an ATR-FTIR based method for the rapid detection of food adulteration in sesame oil. For this purpose, sesame oil was adulterated with hazelnut, canola, and sun flower oils in different concentrations ranged from 1 to 50%. Cluster analysis of FTIR spectra was performed for differentiation and classification of pure sesame oil from adultured vegetable oil samples. In addition, a calibration curve was obtained to determine relationship between actual adulterant concentration and FTIR predicted concentrations using partial least square (PLS) method for each oil samples. According to these results, it could be concluded that ATR-FTIR technique has a potential for adulteration of sesame oil as a non-destructive, rapid, and effective alternative method.     

Discriminant analysis of Mediterranean pine nuts (Pinus pinea L.) from Chilean plantations by near infrared spectroscopy (NIRS)

Pinus pinea L. is one of the most important nut species in the world given the high nutritional and culinary value of its seed, the pine nuts, with increasing demand. The objective of this study was to assess the potential of visible and near infrared spectroscopy (VIS + NIRS) to analyse different sample presentations and to discriminate geographical origins of Mediterranean pine nut grown in Chile. Pine nuts were collected from 76 adult trees in three growth macrozones previously defined for stone pine in Chile. Original spectroscopic data were obtained by means of a Foss NIRSystems 6500 SYII spectrophotometer using a transport module. Reflectance was employed in the wavelength range of 400–2500 nm. The best means of sampling for the pine nuts used in this study were also studied. After analysing the spectroscopic data, discriminant models were obtained by means of discriminant partial least square (DPLS) with all samples. For the three macrozones previously identified, 87.8% of samples was correctly classified in the cross validation stage with the best model for pine nuts spectra analysis, obtained with shelled intact pine nuts. Results indicate that NIRS technology is capable of differentiating between pine nut samples of different geographical origins with errors ranging between 12.2 and 9.2%, and demonstrate the potential of VIS + NIRS technology as a rapid and accurate method for predicting the geographical origin of Mediterranean pine nuts.     

Diminution of aflatoxin B1 production caused by an active packaging containing cinnamon essential oil

The antifungal and antimycotoxigenic action of an active package containing cinnamon essential oil have been evaluated against the mold Aspergillus flavus on the aflatoxin B1 production. Two independent experiments were carried out, the first one with cinnamon on a paper diffusion disc placed in vapor phase and the second one with an active PP (Polypropylene) films containing the essential oil. The culture media, exposure time, closure of the Petri dish and cinnamon concentration were evaluated. The first experiment revealed an important reduction on mycotoxin, even when the mold grew, and the action remained for 15 days. The second experiment highlighted the importance of cinnamon concentration on the antimycotoxigenic action, achieving a strong reduction with the sub-inhibitory concentration (2% of cinnamon) and a complete reduction with fungicidal concentration (4% and 6% cinnamon). The UPLC system coupled to a fluorescence detector was optimized for analysis of aflatoxin B1.