Job’s Tears (Coix Lacryma-Jobi) Adaptability in Sa Kaeo Province, East of Thailand, and Their Chemical Properties in an Edible Group for Alternative Ruminant Animal Forage and Supplementary Feed

Abstract

In the past decade, the cultivation of Job’s tears in Thailand has decreased. By contrast, consumption of Job’s tears in Thailand is still high as a functional food. Thus, it needs to be imported in large quantities from other nations. The objectives of this study were to determine the suitability of the different Job’s varieties of Job’s tears in Sa Kaeo province, East of Thailand and then to select a possible variety to evaluate its chemical properties. Then, the data will be used for the conservation and cultivation of Job’s tears in Thailand. Seven varieties of Job’s tears were collected from markets in Thailand from different sources such as Luang Phra Bang province in the Lao People’s Democratic Republic, Nong Khai, Loei and Chiang Rai provinces in Thailand. Firstly, 7 varieties of Job’s tears were grown and the plant growth characteristics were collected to evaluate their adaptability in Sa Kaeo province, Thailand. Secondly, the plant growth characteristics of 4 varieties of edible Job’s tears were recorded chemical properties such as their chemical composition, total phenolic content (TPC), total flavonoid compounds (TFC), DPPH radical scavenging assay, ABTS decolorization scavenging effect and potassium ferricyanide reducing power assay. The statistical data were analyzed by using the one-way analysis of variance (ANOVA) to determine the difference between varieties. The results showed that there are differences between the varieties in plant morphology and chemical properties. Seven Job’s tears plants were classified into 2 groups, an edible and an ornamental group. The Job’s tears seeds of the ornamental group could not be dehulled into kernels. AL1 to AL4 showed a good adaptability in their growth characteristics. AL4 in kernels had the proper CP at 17.78 % (p < 0.001) for use in a ruminant diet. AL2 had high plant height (157 cm), leaf areas (1,714 cm2) and a tiller number (4 - 6 tillers) which were good characteristics for forage utilization. While AL1 and AL4 had high TPC (46.15 and 24.55 mg GAE/g, respectively, p < 0.001) which showed a positive correlation with EE (p < 0.05). The kernels of AL1 and AL4 can be used as functional food.