Food Science

The effect of nano zinc (ZnO) particles in surface enhancement of attenuated total reflection-Fourier transform mid-infrared spectroscopy (ATR-FTIR) has been studied in butter and spread. Due to the health implications associated with consumption of trans fats, the studies also included the determination of band corresponding to trans fats of butter/ spread in the nano-zinc-treated samples. The FTIR spectra of nano-zinc-treated butter showed enhancement of bands related to (-CO ,-CH 2-) at wave number 1,238 cm −1 and (O-CC) band of esters at wave number 1,100 cm −1. Shifting in wave number to 1,150 cm −1 and reduction in its peak intensity was observed with the band corresponding to 1,162 cm −1 (-CO stretch). Reduction in peak intensity of the bands at about 2,915 and 2,850 cm −1 (C-H groups) was also observed. In the case of spread, nano zinc reduced the peak intensities of FTIR bands at 2,915 cm −1 , 2,850 cm −1 (-C-H-(CH 2) stretches), 1,746 cm −1 (-C═O ester), 1,465 cm −1 (-C-H (CH 2 , CH 3)), 1,375 cm −1 (-C-H (CH 3)) and 1,156 cm −1 (C-O,-CH 2). Trans fats band corresponding to ═C-H stretch (trans bonds, 966 cm −1), was observed in pure butter and spread. Trans fatty acids in butter and spread were quantified with the aid of calibration/ validation standards using trielaidin and triolein and by using partial least squares regression analysis. However, the band at 966 cm −1 was hindered in Zn-treated butter and reduced in Zn-treated spread.

Biofuels demands have motivated the increasing research in production technology as well as effective raw material utilization. Fusel alcohol production had been related with the free amino nitrogen (FAN) content produced during hydrolyses stages and also as a stress response of Saccharomyces cerevisiae. This paper analyses the effect of grain type and endosperm texture on FAN production during starch liquefaction and yeast fermentation of maize, white and red sorghums bioconverted into ethanol. The white sorghum had a harder endosperm texture and upon milling produced a coarser granulation compared to the red counterpart. Therefore, the red sorghum produced higher amounts of FAN during liquefaction and the kinetics of these nitrogenous compounds were metabolized faster during the first hours of yeast fermentation. The white and red sorghums yielded 13.6% and 2.7% lower ethanol compared to the maize counterpart. The white sorghum yielded the lowest amount of ethanol likely to its relatively harder endosperm texture that was less susceptible to biocatalysis and yeast fermentation.

A comparative study of extruded and ground maize meals as raw materials for the production of regular (12 ∘ P) and high gravity (20 ∘ P) worts was devised. Extruded water solubility index (WSI) was higher (9.8 percentage units) and crude fat was lower (2.64 percentage units) compared to ground maize. Free-amino nitrogen compounds (FAN), pH, and glucose were evaluated in regular and high gravity worts produced from ground or extruded maize. Extrusion improved glucose content and ethanol yield. In 20 ∘ P mashes, extrusion is enhanced by 2.14% initial glucose compared with regular ground mashes. The 12 ∘ P and 20 ∘ P extruded treatments averaged 12.2% and 8.4% higher ethanol, respectively, compared to the uncooked counterpart. The 20 ∘ P worts fermented with Zymomonas mobilis produced 9.56% more ethanol than the 12 ∘ P counterpart. The results show that the combination of extrusion and fermentation of 20 ∘ P worts improved ethanol yield per kg flour until 20.93%. This pretreatment stimulates Z. mobilis fermentation efficiency.

A comparative study of extruded and ground maize meals as raw materials for the production of regular (12 ∘ P) and high gravity (20 ∘ P) worts was devised. Extruded water solubility index (WSI) was higher (9.8 percentage units) and crude fat was lower (2.64 percentage units) compared to ground maize. Free-amino nitrogen compounds (FAN), pH, and glucose were evaluated in regular and high gravity worts produced from ground or extruded maize. Extrusion improved glucose content and ethanol yield. In 20 ∘ P mashes, extrusion is enhanced by 2.14% initial glucose compared with regular ground mashes. The 12 ∘ P and 20 ∘ P extruded treatments averaged 12.2% and 8.4% higher ethanol, respectively, compared to the uncooked counterpart. The 20 ∘ P worts fermented with Zymomonas mobilis produced 9.56% more ethanol than the 12 ∘ P counterpart. The results show that the combination of extrusion and fermentation of 20 ∘ P worts improved ethanol yield per kg flour until 20.93%. This pretreatment stimulates Z. mobilis fermentation efficiency.

The effect of nano zinc (ZnO) particles in surface enhancement of attenuated total reflection-Fourier transform mid-infrared spectroscopy (ATR-FTIR) has been studied in butter and spread. Due to the health implications associated with consumption of trans fats, the studies also included the determination of band corresponding to trans fats of butter/ spread in the nano-zinc-treated samples. The FTIR spectra of nano-zinc-treated butter showed enhancement of bands related to (-CO ,-CH 2-) at wave number 1,238 cm −1 and (O-CC) band of esters at wave number 1,100 cm −1. Shifting in wave number to 1,150 cm −1 and reduction in its peak intensity was observed with the band corresponding to 1,162 cm −1 (-CO stretch). Reduction in peak intensity of the bands at about 2,915 and 2,850 cm −1 (C-H groups) was also observed. In the case of spread, nano zinc reduced the peak intensities of FTIR bands at 2,915 cm −1 , 2,850 cm −1 (-C-H-(CH 2) stretches), 1,746 cm −1 (-C═O ester), 1,465 cm −1 (-C-H (CH 2 , CH 3)), 1,375 cm −1 (-C-H (CH 3)) and 1,156 cm −1 (C-O,-CH 2). Trans fats band corresponding to ═C-H stretch (trans bonds, 966 cm −1), was observed in pure butter and spread. Trans fatty acids in butter and spread were quantified with the aid of calibration/ validation standards using trielaidin and triolein and by using partial least squares regression analysis. However, the band at 966 cm −1 was hindered in Zn-treated butter and reduced in Zn-treated spread.