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Egg white is considered as one of the best food proteins and hydrolysis can be applied to increase its nutritional value and reveal antioxidant activity. Low molecular weight of egg white hydrolysate was also beneficial for the chronic kidney disease (CKD) sufferers. However, hydrolysis of egg white protein typically results in relatively low yield. Thus, pre-treatment methods to increase yield of hydrolysate should be sought. The objective of this research was to compare the use of ultrasound, microwave, and steam sterilization (121°C) prior to hydrolysis of egg white by 10% (w/w protein) Alcalase on degree of hydrolysis (DH) and antioxidant activity of the hydrolysate. Ultrasound at intensity of 41.5 W/cm² applied to boiled egg white was found to produce hydrolysate with the highest DH of 45.4%. Antioxidant activities of egg white hydrolysate were examined by 2, 2'-azinobis- (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity, ferric reducing antioxidant power (FRAP), and ferrous ion chelating capacity (FICC) assays. Raw egg white subjected to sterilization for 5 min resulted in the hydrolysate exhibiting the strongest ABTS radical scavenging activity with approximately 64% inhibition. In addition, 30-min steam sterilization the most powerful pre-treatment yielding peptides with FRAP of 22 µM Trolox equivalence. Boiled egg white subjected to ultrasound at intensity of 41.5 W/cm² obtained hydrolysate with FICC of 1800 µM EDTA equivalence. Since there were several measured parameters, and pre-treatment methods affected these parameters differently. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to find global mechanisms related to carnosine synthesis in slow-growing Korat chickens (KRC) using a proteomic approach. Methods: M. pectoralis major samples were collected from 10-week-old female KRC including low-carnosine (LC, 2,756.6±82.88 μg/g; n = 5) and high-carnosine (HC, 4,212.5 ±82.88 μg/g; n = 5). Results: We identified 152 common proteins, and 8 of these proteins showed differential expression between the LC and HC groups (p<0.05). Heat shock 70 kDa protein 8, Heat shock 70 kDa protein 2, protein disulfide isomerase family A, member 6, and endoplasmic reticulum resident protein 29 were significantly involved in protein processing in the endoplasmic reticulum pathway (false discovery rate<0.05), suggesting that the pathway is related to differential carnosine concentration in the M. pectoralis major of KRC. A high concentration of carnosine in the meat is mainly involved in low abundances of Titin isoform Ch12 and Connectin and high abundances of M-protein to maintain homeostasis during muscle contraction. These consequences improve meat characteristics, which were confirmed by the principal component analysis. Conclusion: Carnosine synthesis may occur when muscle cells need to recover homeostasis after being interfered with carnosine synthesis precursors, leading to improved muscle function. To the best of our knowledge, this is the first study to describe in detail the global molecular mechanisms in divergent carnosine contents in meat based on the proteomic approach. [ABSTRACT FROM AUTHOR]

Reports that pacific whiting surimi paste was ohmically heated to investigate degradation of myosin heavy chain (MCH) caused by endogenous proteinase over a range of 40-85 degrees Celsius and 0.5-35 min. Description of degradation given; Study methodology; What the proteolytic degradation of actin exhibited; Findings of study; Concluding remarks.

Studies the effect of linear heating rates on textural properties and myofibrillar proteins of pacific whiting and Alaska pollock surimi. What influence gel networks; Materials and methods; Results and discussion; Conclusions.