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In this study, we characterized Zn seed coats adhered on soybean seed surface [Glycine max (L.) Merrill] and then investigated the effects of such coatings on germination and finally monitored the transference of Zn from the coatings to the seedlings. For that, seeds were coated with ZnSO 4 , 40 nm ZnO, and 5 µm ZnO at 4 mg of Zn per kg of seed. The shape and homogeneity of Zn deposits on the seed surface depended on the type of Zn source. X-ray spectroscopy unraveled that before the germination, Zn neither crossed the seed coat nor was biotransformed. Regardless of the particle size, ZnO-based treatments increased germination ratio, seedlings root, and shoot development, whereas ZnSO 4 suppressed them. After sowing, most of Zn on the seed coat was transferred to soil, while less than 13 wt% was assimilated by the seedling 14 days after sowing. Either this minor fraction of Zn was taken up during the imbibition process or absorbed by during seedling growth. Zinc oxide-based treatments represent a viable alternative to Zn supply in order to boost soybean germination and seedling development.

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The effectiveness of corn‐zein edible coatings in blocking oil oxidation on macadamia nuts was studied by using high‐resolution Hydrogen Nuclear Magnetic Resonance (1H NMR) spectroscopy. Formulations with a zein concentration of 4.0% by weight and oleic acid (OA) as a plasticizer in different proportions were evaluated. Accelerated oxidation was conducted by using an O2‐reactor in a 60C water bath. The oil extracted from the nuts at the beginning of the study and after 10 and 30 days into the experiment were analyzed. Results from the 1H NMR analysis exhibited that the major products formed by lipid oxidation were conjugated dienes. The coatings were imperceptible to the naked eye, but textural changes were visible under scanning electron microscopy. The best coating formulation was a combination of zein with 0.25% OA, which completely inhibited oxidation. Plasticizer addition of 0.50 and 1.00% wt, however, had a negative effect on the coating's property as a barrier against oxygen, resulting in higher rates of oxidation than in the uncoated samples. PRACTICAL APPLICATIONS Hydrophobic zein‐based edible coatings, as used in this study, are capable of acting as barriers against oxygen and water vapor by reducing, or even eliminating, undesirable oxidation in unshelled macadamia nuts during long‐term storage. The results of our study have demonstrated the ease of forming stable coatings to reduce oxidative fatty rancidity. The films are invisible to the naked eye and do not produce visible changes in the texture and the color of the coated nuts. This study indicates that zein/oleic acid edible coatings are feasible to use for large‐scale applications, providing an alternative way to improve the oxidative stability and eventually to lengthen the shelf life and quality of macadamia nuts.