Green Methods to Recover Bioactive Compounds from Food Industry Waste: A Sustainable Practice from the Perspective of the Circular Economy.

The worrying and constant increase in the quantities of food and beverage industry by-products and wastes is one of the main factors contributing to global environmental pollution. Since this is a direct consequence of continuous population growth, it is imperative to reduce waste production and keep it under control. Re-purposing agro-industrial wastes, giving them new life and new directions of use, is a good first step in this direction, and, in global food production, vegetables and fruits account for a significant percentage. In this paper, brewery waste, cocoa bean shells, banana and citrus peels and pineapple wastes are examined. These are sources of bioactive molecules such as polyphenols, whose regular intake in the human diet is related to the prevention of various diseases linked to oxidative stress. In order to recover such bioactive compounds using more sustainable methods than conventional extraction, innovative solutions have been evaluated in the past decades. Of particular interest is the use of deep eutectic solvents (DESs) and compressed solvents, associated with green techniques such as microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), pressurized liquid extraction (PLE) and pulsed-electric-field-assisted extraction (PEF). These novel techniques are gaining importance because, in most cases, they allow for optimizing the extraction yield, quality, costs and time.

Assessment of Dietary Exposure to Ochratoxin A in Lebanese Students and Its Urinary Biomarker Analysis.

The present study investigated the dietary and urinary OTA occurrence among 44 Lebanese children. Relying on HPLC-FLD analysis, OTA was found in all the urine samples and in 46.5% and 25% of the 24 h duplicate diet and dinner samples, respectively. The means of OTA levels in positive samples were 0.32 ± 0.1 ng/g in 24 h diet, 0.32 ± 0.18 ng/g in dinner and 0.022 ± 0.012 ng/mL in urines. These values corresponded to margin of exposure (MOE) means of 7907 ± 5922 (neoplastic) and 2579 ± 1932 (non-neoplastic) calculated from positive 24 h diet, while 961 ± 599 (neoplastic) and 313 ± 195 (non-neoplastic) calculated from the urine. Since the MOE levels for the neoplastic effect were below the limit (10,000), a major health threat was detected and must be addressed as a health institutions' priority. Besides, the wide difference between PDIs and MOEs calculated from food and urine suggests conducting further OTA's toxicokinetics studies before using urine to measure OTA exposure.

Identification of a Halogenase Involved in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius.

UNLABELLED: Aspergillus carbonarius is the main responsible fungus of ochratoxin A (OTA) contamination of grapes and derived products. To date, the biosynthetic mechanism of this mycotoxin has been partially elucidated. Availability of genome sequence of A. carbonarius has allowed the identification of a putative gene cluster involved in OTA biosynthesis. This region hosts the previously characterized AcOTAnrps and AcOTApks genes encoding two key enzymes of the biosynthetic pathway. At about 4,400 nucleotides downstream of these loci, a gene encoding a putative flavin dependent-halogenase came out from the annotation data. Its proximity to OTA biosynthetic genes and its sequence analysis have suggested a role in the biosynthesis of OTA, directed to the introduction of the chlorine atom in the C-5 position of the final molecular structure of this mycotoxin. The deduced protein sequence of the halogenase gene, we designated AcOTAhal, shows a high similarity to a halogenase that is located in the OTA cluster of A. niger The deletion of the halogenase gene completely eliminated the production of ochratoxin A in A. carbonarius and determined a significant increase of ochratoxin B, as confirmed by mass spectrometry analysis. Moreover, its expression profile was similar to the two biosynthetic genes previously identified, AcOTApks and AcOTAnrps, indicating a strong correlation of the AcOTAhal gene with the kinetics of OTA accumulation in A. carbonarius. Therefore, experimental evidence confirmed that the chlorination step which converts OTB in OTA represents the final stage of the biosynthetic pathway, supporting our earlier hypothesis on the order of enzymatic steps of OTA biosynthesis in A. carbonarius IMPORTANCE: Ochratoxin A is a potent mycotoxin classified as a possible carcinogen for humans, and Aspergillus carbonarius is the main agent responsible for OTA accumulation in grapes. We demonstrate here that a flavin-halogenase is implicated in the biosynthesis of OTA in A. carbonarius The encoding gene, AcOTAhal, is contiguous to biosynthetic genes that we have already described (nrps and pks), resulting as part of the biosynthetic cluster. The encoded protein is responsible of the introduction of chlorine atom in the final molecular structure and acts at the last step in the pathway. This study can be considered a continuation of an earlier study wherein we started to clarify the molecular basis of OTA biosynthesis in A. carbonarius, which has not been completely elucidated until now. This research represents an important step forward to a better understanding of the production mechanism, which will contribute to the development of improved control strategies to reduce the risk of OTA contamination in food products.

Food coloring agents and plant food supplements derived from Vitis vinifera: a new source of human exposure to ochratoxin A.

Grape pomaces are increasingly being used as starting material in the industrial production of plant food supplements (PFS), food coloring, and tartrates, but they are at risk of ochratoxin A (OTA) contamination, a mycotoxin with nephrotoxic and carcinogenic effects. We analyzed 24 commercial PFS and 13 food coloring samples derived from Vitis vinifera, mainly pomaces, using a HPLC-FLD method for OTA determination. OTA was found in 75% of PFS samples and 69% of food coloring samples at levels of <1.16-20.23 µg/kg and <1.16-32.00 µg/kg, respectively. The four commercial leavening agents containing tartrates were found to be negative for OTA. All eight samples collected in two distilleries that use grape pomaces and wine lees to produce tartrates and other byproducts contained OTA at levels of <1.16-240.93 µg/kg. The high incidence of OTA contamination in PFS and food coloring agents derived from V. vinifera suggests that maximum permitted level(s) should be established for this mycotoxin in these products.

Multiple mycotoxin exposure determined by urinary biomarkers in rural subsistence farmers in the former Transkei, South Africa.

Subsistence farmers are exposed to a range of mycotoxins. This study applied novel urinary multi-mycotoxin LC-MS/MS methods to determine multiple exposure biomarkers in the high oesophageal cancer region, Transkei, South Africa. Fifty-three female participants donated part of their maize-based evening meal and first void morning urine, which was analysed both with sample clean-up (single and multi-biomarker) and by a 'dilute-and-shoot' multi-biomarker method. Results were corrected for recovery with LOD for not detected. A single biomarker method detected fumonisin B1 (FB1) (87% incidence; mean±standard deviation 0.342±0.466 ng/mg creatinine) and deoxynivalenol (100%; mean 20.4±49.4 ng/mg creatinine) after hydrolysis with ß-glucuronidase. The multi-biomarker 'dilute-and-shoot' method indicated deoxynivalenol-15-glucuronide was predominantly present. A multi-biomarker method with ß-glucuronidase and immunoaffinity clean-up determined zearalenone (100%; 0.529±1.60 ng/mg creatinine), FB1 (96%; 1.52±2.17 ng/mg creatinine), α-zearalenol (92%; 0.614±1.91 ng/mg creatinine), deoxynivalenol (87%; 11.3±27.1 ng/mg creatinine), ß-zearalenol (75%; 0.702±2.95 ng/mg creatinine) and ochratoxin A (98%; 0.041±0.086 ng/mg creatinine). These demonstrate the value of multi-biomarker methods in measuring exposures in populations exposed to multiple mycotoxins. This is the first finding of urinary deoxynivalenol, zearalenone, their conjugates, ochratoxin A and zearalenols in Transkei.