No abstract

The phenolic composition and antioxidant potential were determined in grape berries, berry stem, leaves, leaf petiole and shoots of commercially popular variety Kishmish Chornyi (Sharad Seedless) at various stages of maturation. The berries and berry stems at the initial stage of maturation showed high amounts of total phenolics, flavonoids, flavonols, flavan-3-ols and antioxidant activity in terms of ferric reducing antioxidant power (FRAP). The effect of maturation was profound in grapes with a drastic reduction in various phenolic components and the FRAP value. The berries obtained at the last two harvests showed high anthocyanins and reducing sugars, but the least amount of all phenolic components and thus the antioxidant activity; however, berry stems, leaves, petioles and shoots, respectively, showed 7.6-, 2.9-, 2.3-and 1.5-fold higher FRAP values than berries. Thus, besides the berries, different grapevine parts could also become a potential source of phenolics for pharmaceuticals or functional foods.

Grape byproducts are a rich source of phenolics having immense medicinal properties, but usually wasted from juice/wine processing industries. The present study investigates the phenolic antioxidants and the insulinotropic effect of extracts prepared from seed, skin and stems of two red wine grape cultivars: Pusa Navarang and Merlot. Pusa Navarang cultivar has shown high amounts of total phenolics (95.8 mg/ml), flavonoids (30.5 mg/ml) and flavan-3-ols (21.8 mg/ml) in seed extract and total anthocyanin (4.9 mg/ml) in its skin extract as compared to Merlot cultivar. As determined using HPLC, higher amounts of catechin hydrate (14909 mg/l) and epicatechin (9299 mg/l) were observed in its seed extract, while quercetin hydrate (5849 mg/l) was abundant in its skin extract. Similarly, ferric reducing antioxidant power (FRAP) and ABTS + . [2,2′-azinobis (3-ethylbenzothiazoline)-6-sulfonic acid] and DPPH. (1,1-diphenyl-2-picrylhy-drazyl) radicals scavenging, were higher in its seed extract, respectively being 134.8 mg/ml of Quercetin equivalent (QE), 18.7 mM of trolox equivalent (TE) and 33.5 mM of TE. Strong correlation was obtained between FRAP and total phenolics, flavonoids and flavan-3-ols contents with correlation coefficients (r 2 ) of 0.915, 0.738 and 0.838 respectively. Interestingly, there was a 2-8 fold increase in insulin secretion by isolated mice pancreatic islets at 5.5 mM and 16.5 mM glucose concentration in presence of various extracts. Overall, the seed, skin and stem byproducts of both cultivars are rich sources of phenolics and antioxidants and represent a source of new insulin secretagogues.

As a class of mycotoxins with regulatory and public health significance, aflatoxins (e.g., aflatoxin B1, B2, G1 and G2) have attracted unparalleled attention from government, academia and industry due to their chronic and acute toxicity. Aflatoxins are secondary metabolites of various Aspergillus species, which are ubiquitous in the environment and can grow on a variety of crops whereby accumulation is impacted by climate influences. Consumption of foods and feeds contaminated by aflatoxins are hazardous to human and animal health, hence the detection and quantification of aflatoxins in foods and feeds is a priority from the viewpoint of food safety. Since the first purification and identification of aflatoxins from feeds in the 1960s, there have been continuous efforts to develop sensitive and rapid methods for the determination of aflatoxins. This review aims to provide a comprehensive overview on advances in aflatoxins analysis and highlights the importance of sample pretreatments, homogenization and various cleanup strategies used in the determination of aflatoxins. The use of liquid-liquid extraction (LLE), supercritical fluid extraction (SFE), solid phase extraction (SPE) and immunoaffinity column clean-up (IAC) and dilute and shoot for enhancing extraction efficiency and clean-up are discussed. Furthermore, the analytical techniques such as gas chromatography (GC), liquid chromatography (LC), mass spectrometry (MS), capillary electrophoresis (CE) and thin-layer chromatography (TLC) are compared in terms of identification, quantitation and throughput. Lastly, with the emergence of new techniques, the review culminates with prospects of promising technologies for aflatoxin analysis in the foreseeable future.

A multiresidue method for the analysis of 168 pesticides in dried powdered ginseng has been developed using acetonitrile or acetone mixture (acetone/cyclohexane/ethyl acetate, 2:1:1 v/v/v) extraction, solid-phase extraction (SPE) cleanup with octyl-bonded silica (C(8)), graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, and capillary gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). The geometric mean limits of quantitation (LOQs) were 53 and 6 microg/kg for the acetonitrile extraction and 48 and 7 microg/kg for the acetone-based extraction for GC-MS/SIM and GC-MS/MS, respectively. Mean percent recoveries and standard deviations from the ginseng fortified at 25, 100, and 500 microg/kg using GC-MS/SIM were 87 +/- 10, 88 +/- 8, and 86 +/- 10% from acetonitrile extracts and 88 +/- 13, 88 +/- 12, and 88 +/- 14% from acetone mixture extracts, respectively. The mean percent recoveries from the ginseng at the 25, 100, and 500 microg/kg levels using GC-MS/MS were 83 +/- 19, 90 +/- 13, and 89 +/- 11% from acetonitrile extracts and 98 +/- 20, 91 +/- 13, and 88 +/- 14% from acetone extracts, respectively. Twelve dried ginseng products were found to contain one or more of the following pesticides and their metabolites: BHCs (benzene hexachlorides, alpha-, beta-, gamma-, and delta-), chlorothalonil, chlorpyrifos, DDT (dichlorodiphenyl trichloroethane), dacthal, diazinon, iprodione, quintozene, and procymidone ranging from <1 to >4000 microg/kg. No significant differences were found between the two extraction solvents, and GC-MS/MS was found to be more specific and sensitive than GC-MS/SIM. The procedures described were shown to be effective in screening, identifying, confirming, and quantitating pesticides in commercial ginseng products.