The deeply oxidized pork fat (PF) is the key in the production of Chi-aroma Baijiu, a Chinese distilled spirit. Previous studies have not proposed an integrated method to promote lipid oxidation of PF, and the formation of volatiles has not been studied. In this work, an efficient method was established to promote lipid oxidation and release of volatiles of pork fat pulp (PFP) in an integrated treatment for the production of Chi-aroma Baijiu. The results showed that the acid value of PFP by lipase pretreatment (T1) was significantly elevated (p < 0.05), compared to the control (T0). Lipase-blue light-riboflavin-25 • C (T2), lipase-open vial-dark-25 • C (T3), and lipase-dark-40 • C (T4) further promoted lipid oxidation and reached the oxidation level of PFP by F0, while T2 show the best results. The peroxide value of PFP by T2, T3, and T4 was 41.96-, 16.70-and 14.20-fold higher, and the para-anisidine value was 27.13-, 6.94-and 6.70 fold higher than that in T1. The flavor and volatile analyses showed that PFP by T2 had higher response values than T0 at six electronic nose sensors. T2-T4 promoted the release of volatiles and T2 showed the best result. T2 potentially facilitated lipid oxidation, esterification, and substance exchange of PFP, resulting in a higher type (78.57%) and content (114.50%) of volatiles than T0. The integrated treatment with lipase hydrolysis, blue light with riboflavin could promote lipid oxidation and volatiles release to improve production efficiency of deeply oxidized PF. The results would be viably applied to the production of Chi-aroma Baijiu.

The sound source of violin is string vibration. By the stick–slip friction action between bow and string of violin, string and bridge form a complicated vibration system. The interaction mechanism of bowstring is very intricacy. In this paper, through theoretical analysis and experiment, the vibration behavior of violin string is investigated. We measured the vibration images of bowing and plucking violin string on a high-speed photography optical platform and got two different character of string vibration, including vibration displacement, velocity and space trajectory of the mark point on string. By comparing the displacement curves of the different points among on string, the variety of the ratio of positive process time to negative one of vibration sawtooth waveform are studied, and also the formation process of string vibration enveloping curve. On this basis, the Helmholtz motion of string vibration which is presented at 1862 is studied.