Effect of low temperature conditioning on flavor precursors of ‘Coreano’ garlic (Allium sativum L.) "seed" cloves
Garlic (Allium sativum L.) is widely cultivated around the world and it is well known due to its flavoring and medicinal properties, both characteristics attributed to a number of volatile organosulfur compounds known as thiosulfinates. Our working group previously reported that seed bulbs from 'Coreano' cultivar conditioned at 5°C for 5 weeks accelerated the crop cycle and increased the synthesis of phenolic compounds; however, there is little information on the variation in the levels of organosulfur compounds within low temperature conditioned garlic cloves. The aim of this work was to examine the effect of low temperature conditioning (5°C) or room temperature (20°C) on the levels of several organosulfur compounds in garlic seed cloves. Two sets of garlic 'Coreano' "seeds" were cultivated at Aguascalientes, Mexico during the crop cycle 2014-2015; one set was stored at room temperature (20°C), and the other was conditioned at low temperature (5°C) for 5 weeks. Pungency was determined by the pyruvic acid colorimetric assay and qualitative determination of allicin and other thiosulfinates were obtained using an HPLC-DAD system comparing the chromatograms and UV-spectral data against the literature. The results showed that garlic seed cloves conditioned at 5°C and at room temperature showed no significant differences in production of pyruvic acid. Four thiosulfinates were identified in the chromatograms of both conditions. The average relative content (%) suggested that allicin was significantly increased in low temperature conditioned garlic "seed" cloves compared with those conditioned at room temperature. While the levels of the other three identified thiosulfinates were increased at room temperature conditioning. Furthermore, the results propose that low temperature conditioning affected the accumulation of flavor precursors in garlic seed cloves though further research is needed to establish a better understanding of individual thiosulfinates influence on garlic flavor development.
González-Orozco, B.D., Rivera-Pastrana, D.M., Vázquez Barios, Ma.E., Mercado-Silva, E.M. and Dufoo-Hurtado, M.D. (2019). Effect of low temperature conditioning on flavor precursors of ‘Coreano’ garlic (Allium sativum L.) "seed" cloves. Acta Hortic. 1251, 139-144
thiosulfinates, allicin, pungency, organosulfur compounds