The physiological responses of habanero pepper plants (Capsicum chinense Jacq.) to foliar applications of zinc sulphate and zinc nano-fertilizer were evaluated in greenhouse trials. The effect of the supplement on fruit quality of habanero pepper was particularly observed. Habanero pepper plants were grown to maturity, and during the main stages of phenological development, they were treated with foliar applications of Zn at concentrations of 1000 and 2000 mg L−1 in the form of zinc sulfate (ZnSO4) and zinc oxide nanoparticles (ZnO NPs). Additional Zn was not supplied to the control treatment plants. ZnO NPs at a concentration of 1000 mg L−1 positively affected plant height, stem diameter, and chlorophyll content, and increased fruit yield and biomass accumulation compared to control and ZnSO4 treatments. ZnO NPs at 2000 mg L−1 negatively affected plant growth but significantly increased fruit quality, capsaicin content by 19.3%, dihydrocapsaicin by 10.9%, and Scoville Heat Units by 16.4%. In addition, at 2000 ZnO NPs mg L−1 also increased content of total phenols and total flavonoids (soluble + bound) in fruits (14.50% and 26.9%, respectively), which resulted in higher antioxidant capacity in ABTS (2,2′azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl), and FRAP (ferric reducing antioxidant power) (15.4%, 31.8%, and 20.5%, respectively). These results indicate that application of ZnO NPs could be employed in habanero pepper production to improve yield, quality, and nutraceutical properties of fruits.

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Thermal processing treatment of a roasted purple maize beverage was shown to be effective for reducing the microbiological growth since, after thermal treatment, microbial development was not detected. Physicochemical parameters, soluble solids, pH, and titratable acidity were not affected by the treatment, while L * , a * , b * , C * , and h chromatic parameters showed statistical differences. However, the visual aspects were not affected by the different thermal processing treatments. In terms of mineral content, the main effects were observed on Na, Mn, Cu and Zn concentrations. The thermal processing treatments resulted in higher contents of total phenols, total flavonoids, and total anthocyanins, while condensed tannins were not detected following any of the treatments. HPLC analysis detected ferulic acid in all treatments. On the other hand, chlorogenic acid was detected only in the control, while caffeic acid was detected in all thermal treatments, which means that caffeic acid is released from chlorogenic acid by thermal processing. The DPPH and FRAP antioxidant capacity levels were higher following thermal processing treatment, while the ABTS assay showed a contrasting behaviour. Rezumat Procesarea termică a băuturilor pe bază de porumb este cunoscut a fi eficientă din punct de vedere microbiologic. Parametrii fizico-chimici, pH-ul și aciditatea nu au fost afectate de procesul tehnologic, în timp ce parametrii cromatici ai L * , a * , b * , C * și h au prezentat diferențe statistice. Cu toate acestea, aspectele vizuale nu au fost afectate de diferite tratamente termice de procesare. În ceea ce privește conținutul mineral, efectele principale au fost observate pentru Na, Mn, Cu și Zn. Tratamentul termic a condus la creșterea fenolului, a flavonoidelor și a antocianilor totali, în timp ce taninurile condensate nu au fost detectate. Analiza HPLC a identificat acidul ferulic. Pe de altă parte, acidul clorogenic a fost detectat numai în probele martor, în timp ce acidul cafeic a fost identificat în toate probele analizate, ceea ce relevă că acidul clorhidric este eliberat din acid clorogenic prin procesare termică. Nivelurile antioxidante DPPH și FRAP au fost mai mari după tratamentul termic, în timp ce analiza ABTS a prezentat un comportament contrastant.

The objective of this study was to determine the oxidative stress and the physiological and antioxidant responses of coriander plants (Coriandrum sativum) grown for 58 days in soil with zinc oxide nanoparticles (ZnO NPs) and zinc sulfate (ZnSO4) at concentrations of 0, 100, 200, 300, and 400 mg of Zn/kg of soil. The results revealed that all Zn compounds increased the total chlorophyll content (CHLt) by at least 45%, compared to the control group; however, with 400 mg/kg of ZnSO4, chlorophyll accumulation decreased by 34.6%. Zn determination by induction-plasma-coupled atomic emission spectrometry (ICP–AES) showed that Zn absorption in roots and shoots occurred in plants exposed to ZnSO4 at all concentrations, which resulted in high levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Only at 400 mg/kg of ZnSO4, a 78.6% decrease in the MDA levels was observed. According to the results, the ZnSO4 treatments were more effective than the ZnO NPs to increase the antioxidant activity of catalase (CAT), ascorbate peroxidase (APX), and peroxidases (POD). The results corroborate that phytotoxicity was higher in plants subjected to ZnSO4 compared to treatments with ZnO NPs, which suggests that the toxicity was due to Zn accumulation in the tissues by absorbing dissolved Zn++ ions.

The genetic improvement program of the Seed Technology Training and Development Center works on the agronomic characterization and the content of bioactive compounds in eight genotypes of habanero pepper. The objective is to select genotypes with good agronomic performance that allow the generation of inbred lines to obtain hybrids. In this study, the agronomic performance and the content of bioactive compounds (capsaicinoids, polyphenols, and antioxidant capacity) were evaluated in eight genotypes of habanero pepper grown in the southeast of Coahuila, Mexico, identified as HNC-1, HNC-2, HNC-3, HNC-4, HNC-5, HNC-6, HNC-7, and HCC-8. The plants were grown in a greenhouse for 127 days, under a completely randomized design with four replications each. The results revealed that the yield (g∙plant−1) and number of fruits per plant did not show significant differences between genotypes. However, for the fruit length, the genotypes HCC-8, HNC-7, HNC-6, and HNC-5 stood out with over 40 mm, while in equatorial diameter of the fruit, HCC-8, HNC-4, and HNC-2 stood out with 26.45, 26.46, and 25.12 mm, respectively. The results of the chemical analyses allowed us to identify that HNC-5 and HNC-6 had the highest capsaicin concentration (931.38 and 959.77 mg∙kg−1), dihydrocapsaicin (434.95 and 445.89 mg∙kg−1), Scoville Heat Units greater than 210,000, total phenols (67.54 and 71.15 mg/100 g) and total flavonoids (34.21 and 38.29 mg/100 g), respectively. The HNC-1 and HNC-6 genotypes had the highest carotenoids concentration with 103.96 and 105.07 mg/100 g, and HCC-8 registered the highest anthocyanin content with 22.08 mg C3GE/100 g. The antioxidant capacities showed significant differences (p ≤ 0.05) between genotypes, with a range of 43.22 to 110.39 µmol TE/100 g, 72.37 to 186.56 µmol TE/100 g, and 191.41 to 244.98 µmol TE/100 g for the tests of DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), and FRAP (ferric reducing antioxidant power). The results of this research will be used to select habanero pepper genotypes that can be used in genetic improvement programs to increase the productive potential and the content of bioactive compounds in the fruits to expand their applications in the food industry.