The Physicochemical Changes of Black Garlic during Thermal Processing

Mengmeng Lei,Rui Liu,Mengying Xu,Min Zhang,Zesheng Zhang

doi:10.19026/ajfst.7.1633

Abstract

To explore the physicochemical changes of black garlic during the thermal processing steps and further reveal the role of Maillard reaction in the formation mechanism of black garlic. The physicochemical changes including UV-Vis absorbance, fluorescence and color difference were determined. The UV absorbance at 294 nm and browning intensity at 420 nm gradually increased with increasing heating time, while the fluorescence intensity showed a maximum value at the heating time of 3 days. The color value of black garlic increased after heating at 70-80°C for 10 days. These results indicated Maillard reaction was primarily responsible for the formation of black garlic.

Highlights

Garlic (Allium sativum L.) is widely used as foods and spices in many countries for thousands of years
UV absorbance at 420 nm is often used as an indicator of the extent which the Maillard reaction takes place in foods and it symbolizes the final stages of the browning reaction
The appearance of premelanoidins and the formation of melanoidins could be monitored by UV absorbance at 420 nm, which has been used as the end-point measurement for quantifying the yield of high molecular weight melanoidins

Summary

Introduction

Garlic (Allium sativum L.) is widely used as foods and spices in many countries for thousands of years. It has been used as herbal remedies for the treatment of various epidemic diseases, such as fever, headache, cholera and dysentery (Kodera et al, 2002; Corzo et al, 2007). Garlic has attracted much attention for disease prevention because of its beneficial effects, including antibacterial, antioxidant and anticancer activities. Many investigations have demonstrated that black garlic, compared with fresh garlic, has a wide range of beneficial health effects, such as anti-tumor (Wang et al, 2012), antioxidant (Sato et al, 2006), anti-allergic (Kim et al, 2012), antiinflammatory (Purev et al, 2012), hypocholesterolaemic and hepatoprotective activities (Kim et al, 2011a). Black garlic was found to improve insulin sensitivity and dyslipidemia in db/db mice significantly (Lee et al, 2009), thereby possibly managing diabetes and enhancing the immune system (Wang et al, 2010)

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