Seog-Won Lee

Comparing the histochemical characteristics and meat quality traits of different pig breeds

The purpose of this study was to compare the muscle histochemical characteristics and meat quality traits between Berkshire, Landrace, Yorkshire, and crossbred pigs. A total of 594 pigs were evaluated. A clear difference between histochemical properties was observed from the results for fiber type composition. In Berkshire pigs, the area percentage of type I fibers was higher (P<0.001) and that of type IIb fibers was lower (P<0.05) than those of other breeds. The muscle pH(45min) and pH(24h) were significantly higher in Berkshire pigs. Drip loss and color parameters were significantly different between the breeds (P<0.001). The Berkshire pigs, which showed the highest muscle pH and lowest drip loss and L(∗) values, contained a significantly higher percentage of type I fibers than the other breeds. By comparing the fiber type compositions of the different breeds, the results imply that the longissimus dorsi muscle of Berkshire pigs is more oxidative than that of other breeds. A high pH value in Berkshire pigs is due to a high percentage of type I fibers and a low percentage of type IIb fibers. Based on these results, we conclude that muscle fiber composition can explain in parts the variation of meat quality across and within breeds.

Use of electrical conductivity to predict water-holding capacity in post-rigor pork

This study was designed to re-examine the interrelationships among ultimate pH (pH(u)), electrical conductivity (EC) and water-holding capacity (WHC), and to test if EC, using one of two EC instruments, and pH(u) can be used to predict WHC. The % drip (PD) was used as measure of WHC. Forty-seven pork loins were classified either as PSE (pale, soft, exudative), RSE (reddish-pink, soft, exudative), RFN (reddish-pink, firm, non-exudative) or DFD (dark, firm, dry), based on L* values, PD and pH(u.) The measurement of EC, conducted using the instrument developed at the University of Wisconsin-Madison (UW-EC) was highly correlated to PD at 24 h post mortem (CD=66%), but the pH (NWK) measure of EC was not as highly related to WHC as UW-EC. The predictive value of pH(u) and EC for WHC were similar. When 47 samples were divided into three different groups, such as low (< 2% drip), medium (2-6% drip) and high (> 6% drip) drip loss, UW-EC alone grouped 80% of the samples correctly. Thus, EC seemed to be an accurate predictor of WHC in pork muscle when measured at 24 h post mortem. It is conceivable that EC can be used independently, or with even better success in combination with pH(u), to classify WHC of pork carcasses.

Ultrasound-guided radiofrequency neurotomy in cervical spine: sonoanatomic study of a new technique in cadavers

AIM To develop an ultrasound-guided technique for radiofrequency (RF) cervical medial branch neurotomy and to validate the accuracy of this new method. MATERIALS AND METHODS Five non-embalmed, fresh cadavers were used; three male and two female cadavers with a median age at death of 67.2 years (range 50-84 years). This study was conducted in two parts. First, two of the cadavers were used to define the sonographic target point for RF cervical medial branch neurotomy using high-resolution ultrasound (12 to 5 MHz). The needles were guided to five consecutive cervical medial branches in the cadavers under ultrasound guidance. Subsequently, the position of the ultrasound-guided needle was verified using C-arm fluoroscopy. Ultrasound-guided RF neurotomy was performed to the C5 medial branches in all five cadavers. In the three cadavers not used in the first part of the study, ultrasound-guided RF neurotomy without C-arm fluoroscopic confirmation was performed to the C3-C7 medial branches. The accuracy of neurotomy was assessed by pathological examination of the cervical medial branches obtained through cadaver dissection. RESULTS In all five cadavers, the sonographic target point was identified in all C3-C7 segments with the 12 to 5 MHz linear transducer. In all 20 needle placements for the first and second cadavers, C-arm fluoroscopy validated proper needle tip positions. In all five cadavers, successful neurotomy was pathologically confirmed in 30 of 34 cervical medial branches. CONCLUSIONS Ultrasound-guided cervical medial branch neurotomy was successfully performed in 30 of 34 cervical medial branches in five cadavers. However, before eliminating fluoroscopic validation of final needle tip positioning, the technique should be validated in symptomatic patients.

Effect of ion fluid injection on beef tenderness in association with calpain activity.

Sodium pyrophosphate plus sodium chloride (PPi) was injected into pre-rigor, hot boned biceps femoris (BF) and semimembranosus (SM) muscle from 12 heifer carcasses. The PPi injection caused higher pH values between 10 and 48 h post-mortem than found in the controls for both muscles (P<0.05). PPi injection resulted in faster decreases in the activities of μ-calpain and calpastatin than in the control for both muscles with time post-mortem (P<0.05). There were significant differences between treatments in both the BF and SM (P<0.05). There was evidence that PPi-injection elevated pH, and accelerated activation of calpains, resulting in improved tenderness. The rates of degradation of titin and troponin-T as well as the appearance of 95 and 30 kDa peptides were faster in the PPi-injected muscles than the controls. PPi-injection elevated muscle pH, which was attributed to acceleration of the calpain activation. It is concluded that PPi-injection improved beef tenderness by accelerating activation of calpain.

Influence of Steeping Solution and Storage Temperature on the Color Change of Garlic

UNLABELLED The objective of this study was to investigate the browning of garlic under different steeping conditions and storage temperatures. The brown indices of steeped garlics showed lowest values (7.3 and 7) in 25% and 50% EtOH at 7 d of storage. The degree of browning of steeped garlics was lowest (10.2 in 25% EtOH and 10.4 in 50% EtOH) in the samples soaked for 8 h at 13 d of storage. As the storage temperature was increased from 10 to 40 degrees C, the brown indices of garlics revealed an increasing trend relative to storage time regardless of steeping treatment. Overall, the kinetic parameters showed relatively low R(2) and irregular reaction constants, but the k(o) values showed an increasing trend with temperature under a zero-order model. The highest polyphenol content within the garlic bulbs was seen in controls (without steeping treatment, 588.9 microg/g), than 0% EtOH (water, 392.5 microg/g), than 25% EtOH (211.3 microg/g), and finally 50% EtOH (155.6 microg/g). The polyphenol oxidase activity of garlic showed a similar trend to that of polyphenol content. However, the texture properties of garlics steeped with 25% and 50% did not change. PRACTICAL APPLICATION The garlic color preferred by consumers is a creamy-white, but this is susceptible to enzymatic browning when pre-peeled and chopped. When garlic was steeped in the 25% and 50% alcohol, the browning of garlic was prevented during storage.