Wheat Germ and Lipid Oxidation: An Open Issue

Abstract

Wheat germ (WG)’s shelf life after the milling process is incredibly short because of the presence of enzymes that aggravate the oxidation process; thus, stabilization is required in order to exploit the nutrients and bioactive compounds within WG. The critical point for the oxidation process is the mechanical treatment used to separate WG from the kernel, which exposes the lipid fraction to the air. Showing the connection between the quality of durum wheat, considering its storage management, and wheat germ oil (WGO), extracted with a cold press, solvent and supercritical CO2, is the aim of the study. The acidity and peroxide values were analyzed to evaluate lipid oxidation, while fatty acids, tocols, sterols and policosanols were evaluated for WGO characterization. The first fundamental step to control lipid oxidation is raw material management. Subsequently, the tempering phase of durum wheat, which is applied before the degermination process, is the most critical point for oxidation to develop because of the increase in moisture in the caryopsis and the activation of lipase and lipoxygenase. This represents a paradox: in order to stabilize the germ with degermination, first it seems inevitable to carry out a process that destabilizes it. To retains its highest quality, this will lead to a better use of the whole grain by reducing WG and by-product waste.

Some Semen Characteristics and Oxidant/Antioxidant Markers of Chilled Diluted Rabbit Semen in Tris-Based Extender Supplemented with Wheat Germ Extracts

“…Also, the highest fatty acid was the linolic acid (50.90%). Concerning the unsaponifiable matter, for the WG oil, our results agreed with Marzocchi et al [44], who reported that WG oil contains campesterols (18.5%) and sitosterol (18.8%).…”

Possibility of using wheat germ and wheat germ protein isolate for high‐protein pasta production

“…The amino acid composition of wheat germ protein is similar to that of the reference protein reported by Food and Agriculture Organization (FAO) (Boukid et al, 2018; FAO, 2007; Liao et al, 2020). Due to the high content of enzymes, for example, lipase and lipoxygenase, and the presence of unsaturated fatty acids, wheat germ is characterized by a short shelf life (Marti et al, 2014; Marzocchi et al, 2022). Currently, many physical, chemical, and biological methods are used to extend the shelf life of wheat germ (Boukid et al, 2018; Liao et al, 2020).…”

Lipid Process Markers of Durum Wheat Debranning Fractions

“…Oil was extracted using a Soxhlet apparatus (Behr Labor-Technik, Fischer Scientific Italia, Milano, Italy), as reported by Marzocchi et al [ 8 ] and in accordance with the AOAC Official Method [ 9 ] (AOAC International Website). About 10 g of ground wheat fractions were placed in a cellulose thimble, and oil was extracted using a refluxing n ˗hexane.…”

“…The procedure for sterol analysis was the same as reported by Marzocchi et al [8]. After the addition of 0.5 mL of 5α-cholestan-3β-ol (c = 2 mg/mL) as the internal standard, Foods 2023, 12, 3036 4 of 12 250 mg of oil were saponified with 10 mL of 2 N methanolic potassium hydroxide at room temperature for 20 h [12].…”