Microwave vacuum drying of Pereskia aculeata Miller leaves: Powder production and characterization

Pereskia aculeata Miller (PAM) is a non-conventional leaf vegetable that has drawn attention due to its remarkable nutritional quality, such as a high protein, carotenoids, and vitamin content. This study aimed to produce dehydrated PAM-leaves by air-drying (AD), freeze-drying (FD), and microwave vacuum drying (MWVD), and evaluate the quality and physicochemical properties (moisture, a(w), bulk density, particle density, bed porosity, apparent solubility, dispersion time, and beta-carotene content) of the dried powdered leaves. To produce powders with a(w) lower than 0.4 and moisture content below 6%, MWVD showed a drying time of 1.3 and 0.8 hr using the input power of 300 W and 500 W, respectively; besides, the final drying time for AD and FD was around 10 and 16 hr, respectively. MWVD dried powder showed bed porosity of similar to 67% and solubility around 30%, slightly less porous, and with a similar solubility to the FD-powder. PAM powder dehydrated by MWVD preserved about 66% of the original content of beta-carotene equivalent for both microwave power, which is only 15% lower of the content in the FD-powder, and twice bigger than AD-powder. The MWVD of PAM allowed obtaining high-quality powders comparable to the freeze-dried PAM. Practical Applications:As Pereskia aculeata Miller (PAM) is a leaf vegetable with high protein, carotenoids, and vitamin contents, its powders can be a suitable and stable presentation for a new proteinaceous product. This use of PAM as a powder with high protein concentration is in agreement with the global trend that seeks new plant-based protein sources. In this way, the study of drying processes that result in PAM powders with suitable properties is of interest to researchers and food industries.

Automated summary

The study aimed to produce dehydrated Pereskia aculeata Miller (PAM) leaves using different drying methods and found that microwave vacuum drying (MWVD) preserved about 66% of beta-carotene content, with shorter drying time and high quality, making it suitable for new proteinaceous products.