Underutilized maize kernels (Zea mays L. var. amylacea and var. saccharata) subjected to pan and microwave toasting: A comparative structure study in the whole kernel. (July 2021)

• Record Type: Journal Article
• Authors: Lara, Nelly; Vizuete, Karla; Debut, Alexis; Chango, Iván; Campaña, Orlando; Villacrés, Elena; Bonilla, Pablo; Ruales, Jenny
• Is Part Of: Journal of cereal science. Volume 100(2021)
• Publication Date: 2021-07
• Subjects: Maize kernel -- Toasting -- Microwave -- Crystallite size -- Raman -- Intrinsic viscosity; Grain -- Periodicals; Cereal products -- Periodicals; Céréales -- Périodiques; Produits céréaliers -- Périodiques; Cereal products; Grain; Periodicals; 664.705
• DOI: 10.1016/j.jcs.2021.103249
• Languages: English
• ISSNs: 0733-5210

Abstract

Abstract: Toasting in a pan is a household activity to make ready-to-eat maize using the whole kernels of underutilized maize types ( Zea mays L. var. amylacea and var. saccharata ) in the Andean region. Floury (a0 and a1) and sweet (a2) maize kernels with 14 g/100 g moisture content (T0) were subjected to a pan (T1) and microwave (T2) toasting. The comparative evaluation by maize types and kernel conditions (raw and toasted processes) revealed structural variations in starch granule size measured by scanning electron microscopy (SEM). In floury maize, blue value (BV), number average of molecular weight ( M ‾ n ) and intrinsic viscosity [η] evidenced consistent conformational variations. The FWHM ratio 865/941 allowed the differentiation between floury and sweet maize and between raw and toasted kernels. Floury maize displayed high ATR FTIR band intensities in the range of 994–1151 cm −1 and low from 1646 to 3298 cm −1 compared with sweet maize. Microwave toasting exhibited higher (1454–2924 cm −1 ) and lower (3298 cm −1 ) ATR FTIR band intensities than those for raw kernel and toasting in a pan. Microwave toasting had the same effect as toasted in a pan on carbohydrate structure and caused changes linked to the band intensity increases ascribed to protein and lipid structures. Graphical abstract: Image 1 Highlights: Toasting in a pan is used to make edible kernels of Andean specialty maize types. Toasting maize kernel in pan and microwave causes size reduction of starch granules. Floury and sweet maize kernels are different in starch granule crystallinity. Number mean molecular weight and intrinsic viscosity lower by toasting floury maize. The water-soluble index in sweet maize can represent phytoglycogen nanoparticles.