The partial purification and properties of pepsin obtained from Turkey proventriculus

Expression pattern and cellular localization of pepsinogen in early development and induced by different diets in the spotted knifejaw (Oplegnathus punctatus)

To solve the high mortality rate of early-stage larval feed conversion during aquaculture in Oplegnathus punctatus, the investigation of the structural and functional characteristics of the gastric tissue was conducted. Histological results showed that the gastric gland rudiment appeared at 17 dph. The basic structure of the stomach was fully developed between 26 and 35 dph. Two pepsinogen genes, named OpPGA1 and OpPGA2, were identified in the spotted knifejaw genome. qPCR results of developmental period showed that the two genes were low in expression during early development (5 and 15 dph). At 20 dph, the two genes started to show trace expression, and at 30 dph the mRNA expression levels of OpPGA1 and OpPGA2 reached the highest levels. Results of pepsin activity detection during the development period showed lower activity was detected 22 dph, followed by a peak at 30 dph. Under different feeding inductions, OpPGA1 showed the highest expression in the basic diet group and hard-shell group, while the expression level in the phytophagous group remained consistently low. The mRNA expression level of OpPGA2 in the phytophagous group was significantly higher than in other groups. Enzyme activity determination under different feeding inductions showed slightly higher enzyme activity in the basic diet group and crustacean group. The results of in situ hybridization showed that the mRNA of both OpPGA1 and OpPGA2 genes was both expressed in gastric gland cells. These information can contribute to the development of practical feeding methods in terms of digestive physiology for the development of larvae.

An impedimetric sensor based on molecularly imprinted nanoparticles for the determination of trypsin in artificial matrices - towards point-of-care diagnostics

A high-performance impedimetric sensing platform was designed to detect proteins by employing molecularly imprinted polymeric nanoparticles (nanoMIPs) as selective receptors. This was achieved via the combination of the nanoMIPs with a self-assembled thioctic acid (SAM-TA) monolayer onto screen-printed gold electrodes, providing stable covalent attachment of the selective binder to the transducer. Taguchi design has been modelled to achieve the optimal level of sensor fabrication parameters and to maximise the immobilisation of nanoMIPs and their response (e.g. the response of imprinted polymers compared with the non-imprinted control). The developed sensor was tested towards a range of concentrations of trypsin dissolved in ammonium acetate (pH = 6) and showed promising applicability in artificial saliva, with a recovery percentage between 103 and 107%.

Texture Characteristics of Horse Meat for the Elderly Based on the Enzyme Treatment

Horse meat is nutritionally adequate to the elderly, but it has a comparatively hard texture in contrast to most of the food. In practice, the meat intake in the elderly is generally bated because the relatively difficult texture of the meat can diminish mastication. Thus, strategies are being developed to produce meat products remanding detracted mastication exertion and possibly exalt ingestion and nutritional stand, in the elderly. Hence, the effects of enzymes on textural characteristics of horse meat were studied, because they have well-known favorable efficacy on the meat tenderness by causing important demotion of the myo-fibrillar protein and collagen. Four treatments namely, papain, bromelin, pepsin, and pancreatin, alongside one control were invoked to the horse meat. Their effects on the texture parameters were determined. All the above enzymatic treatments significantly reduced hardness and resilience (p<0.001). These results present opportunities to produce essential fatty acids fortified horse meat with soft texture and satisfied technological characteristics. The intake of the essential fatty acids intensified horse meat could aid the elderly to get their aimed essential fatty acid demands. Results also suggest that horse meat tenderized through enzymatic processing stand for auspicious options for the comprehension of texture-revised diets in the elderly population.