The Physicochemical and Nutritional Value of Fresh and Processed Portulacaria afra (Spekboom) Leaves

Abstract

Wild-growing edible flora should be investigated to improve human food sustainability and security. Portulacaria afra (spekboom) is an undervalued edible succulent plant that thrives in harsh conditions in Southern Africa. This study determined whether the indigenous edible spekboom can be harnessed as a sustainable, nutritious food source and ingredient. Physicochemical and nutritional analyses were conducted on fresh and processed leaves (preserves, chutney, pickles, and spice). The physicochemical characteristics included morphology, color, texture, °Brix, pH, water activity, moisture content, titratable acidity, and ascorbic acid. Nutritional value determinants included crude protein, crude fiber, gross energy, and total fat content. The small, dark green fresh leaves had a soft texture and a very low sugar and fat content. Although the water content was high, water activity was low. The pH and titratable acidity showed high acidity. Leaves were high in ascorbic acid and low in protein, energy, insoluble fiber, and total fats. The leaves were successfully processed into preserved products providing possible applications in the food industry other than fresh leaves. The high acidity could be researched for application as a functional ingredient. This study provided basic information on an unexplored plant that may have potential in the food industry.