The anthocyanin's role on the food metabolic pathways, color and drying processes: An experimental and theoretical approach

A critical review on the stability of natural food pigments and stabilization techniques

This comprehensive review article delves into the complex world of natural edible pigments, with a primary focus on their stability and the factors that influence them. The study primarily explores four classes of pigments: anthocyanins, betalains, chlorophylls and carotenoids by investigating both their intrinsic and extrinsic stability factors. The review examines factors affecting the stability of anthocyanins which act as intrinsic factors like their structure, intermolecular and intramolecular interactions, copigmentation, and self-association as well as extrinsic factors such as temperature, light exposure, metal ions, and enzymatic activities. The scrutiny extends to betalains which are nitrogen-based pigments, and delves into intrinsic factors like chemical composition and glycosylation, as well as extrinsic factors like temperature, light exposure, and oxygen levels affecting for their stability. Carotenoids are analyzed concerning their intrinsic and extrinsic stability factors. The article emphasizes the role of chemical structure, isomerization, and copigmentation as intrinsic factors and discusses how light, temperature, oxygen, and moisture levels influence carotenoid stability. The impacts of food processing methods on carotenoid preservation are explored by offering guidance on maximizing retention and nutritional value. Chlorophyll is examined for its sensitivity to external factors like light, temperature, oxygen exposure, pH, metal ions, enzymatic actions, and the food matrix composition. In conclusion, this review article provides a comprehensive exploration of the stability of natural edible pigments, highlighting the intricate interplay of intrinsic and extrinsic factors. In addition, it is important to note that all the references cited in this review article are within the past five years, ensuring the most up-to-date and relevant sources have been considered in the analysis.

Effect of Modified Solar Dryers on Colorimetric and Physicochemical Properties of Pumpkin Flower (Cucurbita maxima)

This study aimed to evaluate the solar dryers' cover material effects on the colorimetric and physicochemical properties of pumpkin flowers (Cucurbita maxima). A direct cabinet solar dryer was designed using three cover types: polycarbonate, polyethylene, and aluminum with selective surface (titanium oxide coating). A unifactorial experimental design with three levels was adopted. Pumpkin flower stability was assured by reducing the initial moisture content (95.22%) and water activity (0.989) to 3.15% and 0.276 in the polycarbonate dryer, to 3.03% and 0.279 in the selective surface dryer, and 5.19% and 0.364 in the polyethylene dryer. The drying kinetics showed that the drying time needed to achieve the moisture equilibrium was 480, 540, and 720 min in the respective dryers, depending on the ambient conditions. The initial pumpkin flower hue angle was 76.52°; however, this value decreased to 74.81, 69.52, and 70.23° in the dryers with polycarbonate, polyethylene, and the selective surface respectively; this behavior indicates a pumpkin flower tendency to orange color. The dryer with the selective surface obtained the best properties in pumpkin flowers. The pumpkin flower showed an initial total soluble solid of 1.5°Brix increased to 30°Brix in the polycarbonate and polyethylene dryers and 39°Brix in the selective dryer. The titanium oxide dryer observed an increment in ascorbic acid content from 3.5 to 8.806 mg/100 g, whereas 6.45 and 5.87 mg/100 g in the polycarbonate and polyethylene dryer, respectively.