Effect of Superheated Steam Pretreatment on Storage Quality of Corn Germ

To investigate the effect of superheated steam (SHS) pretreatment on the storage quality of corn germ, samples were subjected to SHS pretreatment at three combinations of temperature and time (150 ℃-60 s, 180 ℃-120 s, and 210 ℃-120 s) followed by 8-week storage in a climate chamber at (25 ± 3) ℃ and relative humidity (RH) of (75 ± 3)%. The physicochemical properties, lipid concomitants, and antioxidant activity were measured during the storage period. The results showed that SHS pretreatment significantly reduced the acid value, peroxide value, conjugated diene and triene contents, p-anisidine value, and total oxidation value of corn germ during storage (P < 0.05). Concurrently, the SHS-pretreated groups exhibited higher retention rates of phenolic compounds and tocopherols compared with untreated controls (P < 0.05). In addition, antioxidant assays revealed that SHS-treated samples exhibited significantly superior 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging capacities, ranging from 105.08 to 122.04 and from 137.55 to 152.62 μmol/100 g, respectively (P < 0.05). Among the different SHS-pretreated groups, the sample treated at 180 ℃ for 120 s exhibited the lowest oxidation level, the highest retention of minor lipid concomitants, and the strongest antioxidant activity during storage. In summary, SHS pretreatment effectively enhanced the storage quality of corn germ. This study provides a novel strategy for stabilizing corn germ and facilitates the industrial application of SHS technology in the field of oil processing.