Effect of thermal-alkaline processing conditions on the quality level of corn oil

Abstract

The objective of this study was to determine the best combination of process variables to produce nixtamalized corn flour (NCF) with the lowest level of lipid deterioration. The nixtamalization conditions used were calcium concentrations from 0.4 to 2.56 g Ca(OH) 2 /L in water and steeping times of 6.34 to 17.65 h. The cooking time was 40 min at 948C. The cooked and steeped grains were washed and milled to obtain masa which was then dehydrated and milled until the NCF was obtained. Oil was extracted by means of hexane from each sample of processed corn. The level of least oil deterioration of nixtamalized samples was based on the following response variables: saponification, acidity, peroxides, iodine values and extinction coefficient measured at 270 nm (K 270 ). The best nixtamalization conditions for obtaining the highest oil stability were found at Ca(OH) 2 lower than 0.75% and steeping times less than 12 h.Keywords: corn; nixtamalization; lipids; oxidation El objetivo de este estudio fue determinar la mejor combinacio´n de las variables de proceso para producir harina de maı´z nixtamalizada (HMN) con el menor deterioro de los lı´pidos. Las condiciones de nixtamalizacio´n usadas fueron concentraciones de hidro´xido de calcio en un rango de 0,4 a 2,56 g Ca(OH) 2 /L en agua y tiempos de reposo de 6,34 y 17,65 h. La temperatura de cocimiento fue de 948C por 40 min. Los granos de maı´z cocidos y reposados fueron lavados y molidos para obtener masa, la cual fue deshidratada y molida hasta obtener la HMN. A cada muestra de maı´z procesado le fue extraı´do el aceite con hexano. El punto donde existio´una menor oxidacio´n de aceite fue basado en las siguientes variables de respuesta: valores de saponificacio´n, de acidez, de pero´xidos, de iodo y el K 270 . Las mejores condiciones de nixtamalizacio´n para obtener la mayor estabilidad del aceite fueron encontradas a concentraciones de Ca(OH) 2 inferiores a 0,75% y tiempos de reposo menos de12 h.

Comparison of the Oxidative Stability and Antioxidant Activity of Extra-Virgin Olive Oil and Oils Extracted from Seeds of Colliguaya integerrima and Cynara cardunculus under Normal Conditions and After Thermal Treatment

“…To verify the quality of the extra-virgin olive oil, specifically the degree of deterioration, we measured the characteristics of the absorption bands between 200 and 300 nm, using UV spectroscopy. We chose this range of wavelength because the primary oxidation compounds (peroxides and hydroperoxides with two conjugated double bonds) absorb at almost 232 nm, whereas the secondary oxidation products, such as aldehydes and ketones, absorb at wavelengths of 266, 270, and 274 nm [35]. For that reason, low absorption in this region is indicative of the oil quality.…”

Chemical, thermal and structural properties of alkaline‐cooked (nixtamalised) chickpea (Cicer arietinum) flours

“…Nixtamalised flours presented a lower fat content than raw samples and a negative correlation with the concentration of in both treatments: WOS and WS (r = −0.93, P ≤ 0.05 and r = −0.96, P ≤ 0.05, respectively). This decrease is produced by the saponification of some free lipids, as reported by Yahuaca-Juárez et al (2013). Regarding ash content, nixtamalised chickpea flours revealed an increase in this component regarding to raw flours, due to the lime added during nixtamalisation.…”

Başlıca Mısır Bileşenleri Üzerine Alkali Pişirmenin (Nikstamalizasyon) Etkileri

“…Yahuaca-Juárez ve ark. [68] yaptıkları çalışmalarında en yüksek yağ stabilitesinin elde edildiği en iyi alkali pişirme koşullarının %0.75 Ca(OH)2 konsantrasyonu ve 12 saatten daha az dinlendirme süresi olduğunu tespit etmişlerdir. In vitro sindirim çalışmaları, uzun zincirli doymuş yağ asitlerinin, yağsız mısır nişastası ile kompleks içerisindeyken, kısa zincirli doymuş ve doymamış yağ asitlerine kıyasla sindirilebilirliği daha fazla arttırmakta olduğunu göstermiştir [69].…”