Evaluation of value adding components from postharvest biomass of Thai medicinal cannabis var. Hang Kra Rog Phu Phan

Thailand has undertaken regulatory reforms to facilitate the cultivation and commercialisation of Cannabis sativa L. for medicinal purposes. The prominent cannabis strain in Thailand is Hang Kra Rog Phu Phan (HRPP), distinguished for its high tetrahydrocannabinol (THC) content. The recent adoption of a biocircular approach within the industry reflects a commitment to minimising losses and enhancing value-added processes. However, there is limited information on biomass generation from the postharvest management of this cannabis strain and the development of value-added products. This study aims to address this gap by conducting a survey of local cannabis farms and evaluating the quantity of cannabis biomass by-product materials resulting from the production process. According to the survey, stems were the most abundant materials followed by leaves and roots. These by-products were subsequently gathered and examined for its chemical components. The results of proximate analysis highlighted that the dried leaves had a high protein content up to 19.27 %, the highest in three types of biomasses. The composition of fat, fibre, ash, and carbohydrates varies depending on the type of biomass. By using sequential extraction, it was found that the extraction yield of pectin in the leaf materials was as high as 13.82 %, and in the stem part, it was at 13.02 %. Meanwhile, cellulose was found in the highest proportion from the roots, at 83.77 %. Confirmation of the composition of polysaccharides using microarray profiling revealed that these biomasses contain various types of polysaccharides (pectin, cellulose, hemicellulose). Analysis of bioactive compounds revealed that the total phenolic and total flavonoid content were the highest in the leaf biomass, consisting of 11.57 and 14.91 mg/g DM, respectively. The leaves also had the highest antioxidant activity. Quantitative analysis of the metabolites in the leaves found contents of rosmarinic acid 2.55 mg/g DM, catechin 2.33 mg/g DM, vanillin 2.32 mg/g DM and in the cannabinoid group, the highest quantity of cannabinol (CBN) 2.63 mg/g DM was found. The findings from this study could serve as a guideline for utilising biomass generated from the production process of cannabis that could be used for pharmaceutical, food, and feed purposes.