Pereskia aculeata Miller is a native cactus that can be found in Brazil and is called 'ora-pro-nobis' (OPN). Many people from poor communities consume the dark green leaves of OPN as a vegetable. The objective of the present work was to evaluate the nutritional components in terms of proximate composition, minerals, vitamins, protein content and their in vitro protein digestibility. OPN leaves showed remarkable levels of total dietary fiber (39.1% dry basis), minerals (calcium, magnesium, manganese and zinc) and vitamins (vitamin A, vitamin C and folic acid). Among amino acids, tryptophan was the most abundant (20.5% of the total amino acids) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed small peptides, inferior to 6.5 kDa, and four major bands (61 kDa, 53 kDa, 33 kDa, and 15 kDa). The protein digestibility corrected amino acid score showed the lowest value of sulfur-amino acids (Met+Cys). OPN leaves could be considered a good source of minerals, vitamins and amino acids, and may serve as a potential functional ingredient.

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In the production of oil from sesame (Sesamum indicum L.) seeds, a coproduct is obtained which is rich in protein and fiber contents. Mixtures of semi-defatted sesame cake (SDSC) (0-20%) and corn grits were processed in a single screw extruder at screw speed ranging from 324 to 387 rpm to improve the nutritional value of corn expanded extrudates. Chemical composition of raw and extruded materials, sectional expansion index (SEI), texture properties, color, paste viscosity, microstructure and sensory analysis of the extrudates were performed. The addition of SDSC increased protein, fat and ash content of corn extrudates, whereas carbohydrate content was reduced. The addition of SDSC reduced the sectional expansion of the corn extrudates and increased puncture force. SDSC-corn extrudates were darker than non-SDSC-corn extrudates. Increasing SDSC increased the number of cells similar to those of commercial corn extrudates with small cells. Sensory analysis showed 20% SDSC-corn extrudates to be acceptable and nutritional balanced. The use of SDSC on corn extrudates up to 20% is an alternative to improve nutritional value keeping good sensory characteristics.

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The diversity of sorghum grains is related to their intrinsic properties, which include starch type, non-starch components and phenolic compounds. The latter are genotype dependent and affect the pericarp characteristics such as color and presence of a pigmented testa. This diversity can be valuable for developing new food products by thermoplastic extrusion intended for human consumption. Flours from sorghum grains from the genotypes of varied pericarp color: white (CMSXS180; 9010032), red (BRS 310; BRS 308) and light brown (BRS 305; 9929034) were processed in a co-rotating twin-screw extruder. Changes promoted by extrusion cooking were evaluated via specific mechanical energy (SME), die pressure, apparent density, sectional expansion index (SEI), water absorption index (WAI) and water solubility index (WSI). Pericarp color affected die pressure, apparent density and WSI values of extrudates. Light brown genotypes, rich in tannin and fiber content, generated the lowest die pressure and SEI values. Red genotypes presented the lowest SME and the highest WAI values. White genotypes presented intermediate SME and the highest die pressure values. These results reflect differences in starch conversion induced by the pericarp type. These results further suggest the potential use of pigmented sorghum extrudates for human consumption.

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Starch is an ingredient used in the formulation of several processed and frozen products, thus, evaluating the stability of gels of different types of starches when submitted to freezing and thawing is of great interest in order to guarantee the quality of the product at the end of the production and distribution chain. Stability of starch gels from non‐conventional sources, i.e. Peruvian carrot (arracacha), sweet potato, white bean and chickpea exposed to five cycles of freezing and thawing was studied by evaluating texture and syneresis. The results were compared to those obtained using commercial starches (native corn, waxy corn and modified waxy corn). The waxy corn and Peruvian carrot starch gels were stable until the third freeze‐thaw cycle studied. The sweet potato starch gel was stable until the second cycle, but presented low syneresis until the fourth freeze‐thaw cycle (2.9%). During the experiment, the Peruvian carrot starch gel lost 5% water at maximum, and the waxy corn and modified waxy corn, 8% and 12%, respectively. The native corn, chickpea and white bean starch gels presented high water losses already in the first cycle. As to texture, the sweet potato and Peruvian carrot starch gels presented greater hardness values than the waxy corn and modified waxy corn starch gels during the entire storage period studied. Until the fourth freeze‐thaw cycle, the modified waxy corn and Peruvian carrot starch gels showed no statistically significant alteration (p≤0.05) in gel hardness. After the first freeze‐thaw cycle, the hardness of the sweet potato starch gel was constant. The same occurred with the gels obtained from chickpea and white bean.