Post-Harvest Processing of Okra (Abelmoschus esculentus L.): A Comparative Review of Drying, Freezing, and Emerging Fermentation Approaches on Phytochemical Stability and Bioactivity

AbstractOkra (Abelmoschus esculentus L.) is a nutrient-rich vegetable, which is inherently very perishable and mainly because it has a high moisture content (۸۸۹۰ ‛ ). As a result, the maintenance of its phytochemical profile requires the introduction of the appropriate post-harvest technologies. The aim of this review is to offer a comparative analysis of the effectiveness of various post-harvest modalities such as: hot air drying (HAD), microwave-vacuum drying (MVD), freeze-drying (FD), infrared drying (ID), and natural convective drying (NCD), and between freezing and blanching pre-treatment in protecting the phytochemical contents of okra. Based on the literature review, it has been observed that freeze-drying is the best post-harvesting technology in preserving the phytochemical composition of okra in terms of the retention of total phenolic content, total flavonoid content, antioxidant activity, vitamin C, and chlorophyll content. However, the process is energy-intensive and requires a longer processing time. Hot air drying at a moderate temperature (۵۰-۶۰°C) is a cost-effective method, but the phytochemical composition of okra is found to degrade considerably. Microwave-vacuum drying is a relatively faster method than hot air drying. Freezing is also found to be effective in preserving the phytochemical composition of okra, but the process requires a continuous supply of electrical energy. Blanching pre-treatment using steam or hot water is found to be effective in preserving the phytochemical composition of okra, but the process results in the loss of water-soluble phenolics and antioxidant compounds. Blanching pre-treatment also enhances the content of carotenoids like β-carotene in okra

کلیدواژه ها:

Abelmoschus esculentus ، Drying Methods ، Freezing ، Blanching ، Phytochemicals ، Antioxidant activity