Effect of the Soil and Ripening Stage in Capsicum chinense var. Jaguar on the Content of Carotenoids and Vitamins

An Analysis of Capsaicin, Dihydrocapsaicin, Vitamin C and Flavones in Different Tissues during the Development of Ornamental Pepper

As a fruit and vegetable crop, the ornamental pepper is not just highly ornamental but also rich in nutritional value. The quality of ornamental pepper fruits is given in their contents of capsaicin, vitamin C (VC), flavonoids and total phenols. The study concentrated on the accumulation of capsaicin and dihydrocapsaicin in different tissues of 18 peppers during fruit growth and development. The results showed that the pericarp and placenta contained significantly higher levels of capsaicin than dihydrocapsaicin. Additionally, the placenta contained significantly higher levels of both capsaicin and dihydrocapsaicin compared to the pericarp. The content of capsaicin was in the range of 0-6.7915 mg·g-1, the range of dihydrocapsaicin content was 0-5.329 mg·g-1. Interestingly, we found that the pericarp is rich in VC (5.4506 mg·g-1) and the placenta is high in flavonoids (4.8203 mg·g-1) and total phenols (119.63 mg·g-1). The capsaicin is the most important component using the correlation analysis and principal component analysis. The qPCR results substantiated that the expression of genes in the placenta was significantly higher than that in the pericarp and that the expression of genes in green ripening stage was higher than that in red ripening stage. This study could be utilized to select the best ripening stages and tissues to harvest peppers according to the use of the pepper and to the needs of producers. It not only provides a reference for quality improvement and processing for consumers and market but also provides a theoretical basis for high-quality pepper breeding.

Genetic Regulation, Environmental Cues, and Extraction Methods for Higher Yield of Secondary Metabolites in Capsicum

Capsicum (chili pepper) is a widely popular and highly consumed fruit crop with beneficial secondary metabolites such as capsaicinoids, carotenoids, flavonoids, and polyphenols, among others. Interestingly, the secondary metabolite profile is a dynamic function of biosynthetic enzymes, regulatory transcription factors, developmental stage, abiotic and biotic environment, and extraction methods. We propose active manipulable genetic, environmental, and extraction controls for the modulation of quality and quantity of desired secondary metabolites in Capsicum species. Specific biosynthetic genes such as Pun (AT3) and AMT in the capsaicinoids pathway and PSY, LCY, and CCS in the carotenoid pathway can be genetically engineered for enhanced production of capsaicinoids and carotenoids, respectively. Generally, secondary metabolites increase with the ripening of the fruit; however, transcriptional regulators such as MYB, bHLH, and ERF control the extent of accumulation in specific tissues. The precise tuning of biotic and abiotic factors such as light, temperature, and chemical elicitors can maximize the accumulation and retention of secondary metabolites in pre- and postharvest settings. Finally, optimized extraction methods such as ultrasonication and supercritical fluid method can lead to a higher yield of secondary metabolites. Together, the integrated understanding of the genetic regulation of biosynthesis, elicitation treatments, and optimization of extraction methods can maximize the industrial production of secondary metabolites in Capsicum.

Evaluation of the Soil Type Effect on the Volatile Compounds in the Habanero Pepper (Capsicum chinense Jacq.)

The aim of this research was to evaluate the effect of soil on the concentration of the main volatile compounds in the Habanero pepper (Capsicum chinense Jacq.). Plants were cultivated in three soils named, corresponding to the Maya classification, as Chich lu’um (brown soil), Box lu’um (black soil), and K’ankab lu’um (red soil). The volatile compounds of the peppers were extracted by steam distillation, analyzed by gas chromatography, and reported on a fresh weight (FW) basis. The results indicated that the soil presented a significative effect on the concentration of the volatile compounds evaluated (1-hexanol, hexyl-3-methyl butanoate, 3,3-dimethyl-1-hexanol, cis-3-hexenyl hexanoate). The peppers cultivated in black soil exhibited the highest concentration of 1-hexanol (360.14 ± 8.57 µg g−1 FW), 3,3-dimethyl-1-hexanol (1020.61 ± 51.27 µg g−1 FW), and cis-3-hexenyl hexanoate (49.49 ± 1.55 µg g−1 FW). In contrast, the highest concentration of hexyl-3-methyl butanoate (499.93 ± 5.78 µg g−1 FW) was quantified in peppers grown in brown soil. This knowledge helps us to understand the role of the soil in the aroma of the Habanero pepper and could be used by farmers in the region (Yucatan Peninsula) to select the soil according to the desired aroma characteristics.