Exploring the potential of solar cooking: impact of parabolic and box models on broccoli quality

Aim: Solar cooking, and associated equipment, take advantage of a large amount of free energy directly offered by the sun. Solar cookers do not need high ambient air temperatures but simply solar radiation, enabling them to play a huge role in sustainability by reducing greenhouse gas emissions, consumption of non-renewable energy and resource depletion. Yet knowledge gaps still exist on solar cooking technical, sustainability, and food nutritional quality impacts. This study aimed to evaluate the impact of solar cooking on the nutritional quality of a food product. Two different solar cookers, a quick (parabolic) and a slower (box) models were considered. Methods: Broccoli (Brassica oleracea L. ssp. Italica) was selected as the primary vegetable for this study due to its recognized nutritional value and abundance of bioactive compounds such as antioxidants, phenolics, and vitamins. Broccoli florets were cooked using two types of solar cookers, parabolic and box, and compared to traditional cooking methods. The time-temperature of the processes was recorded. The physic-chemical properties of the initial and final products were evaluated, including total antioxidant activity, phenolic compounds, carotenoids, chlorophylls, colour, texture, and volatile compounds. A sensory evaluation was also implemented using a trained panel. Available isothermal thermal degradation kinetic data of broccoli quality parameters was used to predict experimental quality retentions after solar cooking. Results: The study concluded that there were no significant differences in the quality of broccoli cooked using either traditional or parabolic solar cooking methods. The integration of the isothermal kinetics for dynamic conditions effectively predicted the quality of solar-cooked broccoli, suggesting the potential use of these models to enhance the utilization and acceptance of environmentally friendly food processing technologies.
Conclusion: This key study revealed that parabolic solar cookers could serve as an alternative to traditional cooking methods without compromising the nutritional properties of broccoli. However, the box-type solar cookers resulted in more significant quality losses. It is important to note that this study represents an initial exploitation, and further research is required to assess the impact of solar cooking on the quality of various food products, considering different cooker models and climatic conditions.