Effect of Lime and Wood Ash on the Nixtamalization of Maize and Tortilla Chemical and Nutritional Characteristics

Abstract

The objective of the study was to obtain information on the chemical composition, functional properties, sensory quality and protein value of tortillas made from the nixtamalization of maize using either lime or wood ashes. The Ca, K, Mg, Fe, and Zn content of lime and wood ashes showed lime to be high in Ca content while wood ash contained more K and about 71% of the Ca content of lime. Both contained relatively high levels of Mg, Fe and Zn, but more so in the wood ashes. The level of reagent for nixtamalization was set at 0.8% of the maize weight. All other processing conditions were kept constant. The pH of the cooking solution was 12.0 for lime and 10.9 for wood ash. The moisture content of maize at 60 min of cooking was 45.8% for both treatments, however after 12 h of soaking, moisture level was 51.0% for the lime treatment and only 46.8% for the ash treatment. Solids (2.4%) in the lime cooking liquor were higher than in the wood ash liquor (1.0%). Chemical composition changes were similar between treatments in masa and tortilla; however, both masa and tortillas absorbed relatively high levels of all minerals including Fe and Zn from the wood ash treatment. The different treatment influenced functional properties particularly hardness and color. Tortilla characteristics were also similar. Protein quality of both alkali cooked products was lower than that of raw corn, more so the product from the wood ash treatment. Although some differences were observed in the sensory studies, human subjects did not dislike the wood ash made tortillas.

The effect of different nixtamalisation processes on some physicochemical properties, nutritional composition and glycemic index

“…Overall, moisture content is similar with data reported by Campechano et al (2012) and Pappa et al (2010) for fresh tortillas elaborated with similar treatments. Differences in moisture content probably are related to water absorption during nixtamalisation and salts used.…”

“…While there are few studies on Classic Nixtamalisation Process (CNP) (Pappa et al, 2010;Gonz alez-Amaro et al, 2015), most authors have focused on TNP mainly on processing parameters as alkali concentration and cooking and steeping times (TrejoGonzalez et al, 1982;G omez et al, 1992;Rodríguez et al, 1996). When wood ashes are used in CNP the resulting nixtamal, masa, flour and tortillas have a different profile in terms of mineral content (Pappa et al, 2010), dietary fibre and resistant starch compared to TNP and ENP.…”

“…When wood ashes are used in CNP the resulting nixtamal, masa, flour and tortillas have a different profile in terms of mineral content (Pappa et al, 2010), dietary fibre and resistant starch compared to TNP and ENP.…”

An empirical test of shell tempering as an alkaline agent in the nixtamalization process

“…A minimum pH of 10.9 was expected to be required for nixtamalization to occur (cf Pappa et al, 2010). Each of the samples that did not reach this threshold were not assessed as having undergone nixtamalization.…”

“…While the cooking and soaking process resulted in each of the ten samples increasing in moisture content, only the three samples that underwent nixtamalization as assessed by pericarp removal showed significant increases in germ moisture content. This indicates that 1) sustained soaking at a pH of 10.9 or above is indeed required for nixtamalization to take place (cf Pappa et al, 2010); and 2) that modest increases in pH likely have no discernible effect on the nutritive value of maize kernels grains because pericarps are not penetrated during the cooking and soaking process, a necessary component in the nixtamalization process.…”