Cold atmospheric‐pressure plasma treatment of turmeric powder: microbial load, essential oil profile, bioactivity and microstructure analyses

• Published in: International journal of food science & technology Vol. 56; no. 5; pp. 2224 - 2232
• Main Authors: Hemmati, Vahid, Garavand, Farhad, Goudarzi, Mostafa, Sarlak, Zahra, Cacciotti, Ilaria, Tiwari, Brijesh K.
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01-05-2021
• Subjects: Antioxidants; Bioactive compounds; Biological activity; Caryophyllene; Cineole; Coalescence; Coalescing; cold plasma; decontamination; Essential oils; Flavonoids; Gas chromatography; Inactivation; Mass spectrometry; Mass spectroscopy; Microorganisms; Microstructure; Oils & fats; Phenolic compounds; Phenols; Plasma; Powder; Scanning electron microscopy; Terpinolene; turmeric powder
• ISSN: 0950-5423; 1365-2621
• DOI: 10.1111/ijfs.14838

Cold atmospheric‐pressure plasma treatment was applied to decontaminate turmeric powder. Cold plasma reduced the aerobic microbial count of turmeric powder by approximately 1.5 log CFU g−1. Cold plasma exerted both improving and deteriorating effects on essential oil profile of turmeric. Cold plasma enhanced total phenolic and flavonoid contents and diminished antioxidant activity. Cold plasma caused damages on microstructure of turmeric powder.
Summary
Turmeric powder treated by cold atmospheric‐pressure plasma (CAPP) at 25 kV for various times of 3, 5 and 7 min was examined for microbial load, essential oil profile, colour parameters, total phenolic content, total flavonoid content, antioxidant activity and microstructure. CAPP treatment caused a reduction of approximately 1.5 log CFU g−1 in aerobic viable cell count of turmeric powder, which was most pronounced during the first 3 min of the treatment. The inactivation kinetic was fitted to the Weibull model with R2 of 0.9913 and RMSE of 0.0641. Gas chromatography–mass spectrometry analysis of essential oils identified twelve different components for turmeric powder of which 1,8‐Cineole, α‐Terpinolene and trans‐Caryophyllene were lost and ar‐Turmerone and α‐Zingiberene experienced considerable increases after plasma treatment. The double‐edged effect of plasma treatment was also observed on bioactivity. Scanning electron microscopy showed formation of super‐agglomerates in plasma‐treated samples due probably to coalescence of the granules with plasma‐damaged walls.