Freeze-drying and oven drying on the nutritional and functional properties of fresh and pre-cooked Xanthosoma taioba leaves

Abstract

ABSTRACT Unconventional food plants (UFPs) are sustainable alternatives for diversifying diets and enhancing the value of Brazilian socio-biodiversity. The nutritional and functional potential of taioba (Xanthosoma taioba E.G. GONÇ.), a UFP, has not been determined. This study aimed to evaluate the nutritional, phytochemical, antioxidant, and aromatic compound profiles of taioba leaves cultivated in a syntropic system in Santo Antônio do Tauá, Pará, Brazil. The taioba leaves were subjected to freeze drying or oven drying with and without prior cooking. This study examined the macronutrients, minerals (inductively coupled plasma optical emission spectroscopy), phenolic compounds, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ferric reducing antioxidant power assays), pigments, color profile, phenolic profile (high-performance liquid chromatography), and volatile compounds (gas chromatography tandem mass spectrometry) in processed taioba leaves. The contents of proteins, insoluble fiber, calcium, and iron were up to 26 g/100 g, 18.44-20.79 g/100 g, 920 mg/100 g, and 30 mg/100 g, respectively. The raw samples exhibited enhanced antioxidant activity and total phenolic contents, indicating the thermal sensitivity of these compounds. The volatile profile markedly varied between the processing methods. Freeze drying preserved alcohols and ketones associated with fruity and herbaceous notes, while oven drying preserved aldehydes and acids associated with oxidation and thermal degradation. Compounds, such as acetoin, promoted the technological and sensory potential of taioba. Thus, the favorable nutritional and functional properties of X. taioba can be harnessed for its application as a food ingredient, improving sustainable agri-food systems and conserving Amazonian biodiversity.