Nutritional characterization and glucose and ß-carotene in vitro bioaccessibility of sweet potatoes and winter squashes, during the storage and cooking

Doctoral thesis abstract

Abstract

The aim of this work was to characterize three cultivars of sweet potato (Arapey, Beauregard and Cuabé) and two cultivars of winter squash (Atlas and Maravilla del Mercado) for total content of glucose, β-carotene, α-carotene, lutein, vitamin C, dietary fiber, dry matter, total polyphenols and total antioxidant capacity, in the pulp cooked in a microwave oven of sweet potatoes and winter squashes stored (14 ºC and 80% RH) for six months. In addition, quantify the in vitro bioaccessibility of glucose and β-carotene and evaluated some nutrients changes in the raw pulp induce by cooking. All data are expressed for 100 grams of fresh weight. Total glucose content in cooked pulp was for Arapey 17.2 g followed by Beauregard (12.4 g) and Cuabé (12.2 g), and four times higer than in winter squashes (3.5 g). Beauregard and Cuabé had a very high content of β-carotene (82.3 and 56.7 mg), while in winter squashes were 3.5 mg. Six times more content of lutein in Cucurbita maxima x Cucurbita moschata (0.489 mg) and seven times less for α-carotene (3.0 mg) than in Atlas (Cucurbita moschata) were measured. The vitamin C content in sweet potato pulp was 33.6 mg and in winter squashes 32.7 mg. The dietary fiber content in Arapey was higher (3.5 g) than Beauregard (2.9%) and Cuabé (2.4 g), being for the two winter squash cultivars (2.9 g). The storage time modified total glucose and carotenoids in sweet potatos and winter squashes, and vitamin C content in cooked pulp of the sweet potatoes. The glucose released in vitro digestion of cooked sweet potato pulp was similar (Arapey 7.1 g, Beauregard 6.0 g, Cuabé 6.3 g) during the six months of storage; while in Maravilla del Mercado (1.2 g) released double than Atlas (0.6 g). The β-carotene released in vitro digestion was higher in Beauregard (5.1 mg) and Cuabé (4.8 mg) than Arapey (0.09 mg), Maravilla del Mercado (0.61 mg) and Atlas (0.13 mg). The cooking determined a reduction of 5% to 20% of the nutrients.