Reducing Ochratoxin A Content in Grape Pomace by Different Methods.

Jianmei Yu,Ivy N Smith,Nona Mikiashvili

doi:10.3390/toxins12070424

Jianmei Yu, Ivy N Smith + Show 1 more

Open Access

https://doi.org/10.3390/toxins12070424

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Abstract

Grape pomace (GP) is the residue of grapes after wine making and is a valuable source of dietary polyphenol and fiber for health promotion. However, studies found the presence of ochratoxin A (OTA) in GP at very high concentrations, which raises a safety issue in the value-added utilization of GP. This study evaluated the effects of thermal pressure, baking, acid and enzymatic treatments on OTA content in GP. Thermal pressure treatment was conducted with wet GP at 121 °C for 10–30 min in an autoclave; acid treatments were conducted with hydrochloric acid, acetic acid, citric acid, and lactic acid, respectively, at 50 °C for 24 h. Baking was conducted using a cookie model. For enzymatic treatment, purified OTA solution was treated with carboxypeptidase A, alcalase, flavourzyme, pepsin, and lipase, respectively, and the effective enzymes were selected to treat GP. Results show that autoclaving for 10–30 min reduced 19–80% of OTA, varying with treatment time and GP variety. The effectiveness of acid treatment was similar to that of autoclaving and varied with acid type and GP variety. Baking increased the detectable OTA. Among all tested enzymes, carboxypeptidase A was the most effective in reducing OTA, followed by lipase and flavourzyme, but their effects were significantly lower in GP samples.

Highlights

Grapes are subject to mold contamination during cultivation, harvest, transport and/or storage.Molded grapes present a safety issue to products derived from grapes because of the presence of mycotoxins
For enzymatic treatment, purified ochratoxin A (OTA) solution was treated with carboxypeptidase A, alcalase, flavourzyme, pepsin, and lipase, respectively, and the effective enzymes were selected to treat Grape pomace (GP)
Key Contribution: This study demonstrates that the OTA content in wet GP can be reduced to a safe level by thermal pressure processing; such as pressure cooking/steaming; or acid treatment

Summary

Introduction

Grapes are subject to mold contamination during cultivation, harvest, transport and/or storage. Molded grapes present a safety issue to products derived from grapes because of the presence of mycotoxins. The major mycotoxin in molded grapes is ochratoxin A (OTA) [1,2]. OTA-producing species are Penicillium verrucosum (P. verrucosum), Aspergillus ochraceus (A. ochraceus), A. niger and A. carbonarius due to their prevalence in foodstuffs (cereals, grapes, coffee, etc.) [3]. Some of our studies show that GP has great potential to serve as an ingredient in food products such as bread, extruded breakfast and cookies at concentrations up to 5% (dry base) [4,5,6]. Previous studies found the presence of OTA-producing fungi

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