Alfalfa seeds biofortification with zinc for production of enriched sprouts

• Hidden hunger affects thousands of people around the world; • Developing low-cost and effective technology can reduce this problem; • Treatment of alfalfa seeds with zinc (ZnSO 4 ·7H 2 O) allowed the production of biofortified seedlings. • 0.015 mmol L -1 of zinc produced the enrichment alfalfa sprout, with adequate biomass and consumer quality. • Plant-based zinc fortification of alfalfa is a viable alternative to producing more nutritious seedlings. Hidden hunger is considered a dilemma, especially in developing countries. The scarcity of micronutrients causes severe health problems by weaking the population's immune system. Biofortified food can mitigate the harm of this problem by assisting specially less favored persons that cannot afford supplements. This study aimed to evaluate the biofortification of alfalfa ( Medicago sativa L.) seeds with zinc (Zn) through osmotic conditioning as a strategy to produce enriched sprouts that contribute to human mineral nutrition and adopt modern analytical tools to verify zn absorption in seedlings. Four rates of zn were tested: 0 mmol L -1 , 0.005 mmol L -1 , 0.010 mmol L -1 , and 0.015 mmol L -1 of zn as ZnSO 4 .7H 2 O. Sprout mass (g), root length (cm) and shoot length (cm), germination rate (%), germination speed index, and zn concentration in the sprouts were evaluated. No significant differences between treatments were observed for sprout mass and germination speed index. However, increases were noticed for root growth and germination rate at estimated doses of 0.0091 and 0.0099 mmol L -1 of zn, respectively. X-ray fluorescence analysis showed zn concentrations as follows: 134, 176, 208, and 288 μg g -1 for the 0, 0.005, 0.010, and 0.015 mmol L -1 of zn treatments, respectively. Biofortification proved a viable tool for plant shoot enrichment, with doses close to 0.010 mmol L -1 resulting in superior plant development and adequate zn accumulation in the sprouts. Osmotic conditioning has proven to be a technological process capable of assisting in food biofortification, and X-ray fluorescence is an adequate analytical tool to measure mineral elements in plant-based food.