Drying of Garlic (Allium sativum) and Its Effect on Allicin Retention

Abstract

Convective hot air-drying and freeze-drying were investigated as potential processes to preserve and concentrate allicin in garlic. Both temperature and air velocity had an important effect on hot air-drying kinetics. Sample size and temperature significantly affected the duration of freeze-drying, and thus the remaining moisture content of the garlic samples. Allicin content decreased with an increase of drying temperature in both convective hot air-drying or freeze-drying. Moderate air temperatures (40 and 50°C) allowed a better allicin retention than higher temperatures (60°C). However, retention of allicin was more important in garlic samples freeze-dried at a temperature of 20°C. The drying method did not show a significant impact on glass transition temperature values, indicating that garlic composition is a more important factor than internal structure. The predictions of the Gordon and Taylor model are in good agreement with the experimental data.

Keywords:

• Allicin
• Freeze-drying
• Garlic
• Hot air-drying

Acknowledgment

The authors are thankful to the Ministère des Relations Internationales de Québec (MRI) and Consejo Nacional de Ciencia y Tecnología (CONYCIT, Mexico) for their financial support. The authors also acknowledge the technical help of Mr. Alain Gaudreau in the HPLC analysis and to undergrad students Aline Batungwanayo, Lorena Moreno, and Zamantha Escobedo for their technical support in the laboratory determinations.

Notes

^a Fresh garlic allicin content: 9224.4±70.4 µg allicin/g dry mass.

^b Averaged values±standard deviation (n = 2).

^c One replicate available with three determinations.

^a Fresh garlic alllicin content: 9224.4±70.4 µg allicin/g dry mass.

^b Averaged values±standard deviation (n = 2).