Transmission of Major and Minor Serum Proteins during Microfiltration of Skim Milk: Effects of Pore Diameters, Concentration Factors and Processing Stages

Investigating biomechanical alterations and emptying patterns after various gastrojejunostomy strategy

Gastrojejunostomy is a prominent approach in managing distal gastric cancer that is unresectable due to gastric outlet obstruction (GOO). Research has demonstrated that stomach-partitioning gastrojejunostomy (SPGJ) exhibits superior clinical efficacy compared to conventional gastrojejunostomy (CGJ), however, the underlying mechanism of this phenomenon remains elusive. This study constructed 3D models of the SPGJ and CGJ based on the computed tomography (CT) images obtained from a patient diagnosed with distal gastric cancer. The biomechanical patterns of these procedures in the digestive system were subsequently compared through numerical simulations and in vitro experiments. The results of the numerical simulation demonstrated that the model following SPGJ promoted the discharge of food through the anastomotic orifice and into the lower jejunum. Furthermore, a decrease in passage size after partitioning, the low-level velocity of esophageal, and an increase in contents viscosity effectively inhibited the flow through the passage to the pylorus, ultimately reducing stimulation to tumor. The study also revealed that favorable gastric emptying is associated with a smaller passage and faster inlet velocity, and that lower contents viscosity. ​The experimental findings conducted in vitro demonstrated that SPGJ exhibited superior efficacy in obstructing the flow near the pylorus in comparison to CGJ. Moreover, a decrease in passage size correlates with a reduction in fluid flow towards the pylorus. These results provide the foundation of theory and practice for the surgical management of patients with GOO resulting from unresectable distal gastric cancer, and have potential implications for clinical interventions.

Transmembrane Pressure during Micro- and Diafiltration of Milk Affects the Release of Non-Sedimentable Caseins

Membrane filtration, especially in combination with diafiltration, can affect the colloidal structure of casein micelles in milk and concentrated milks. The partial dissociation of casein proteins from the casein micelles into the serum phase has been shown to depend on diafiltration conditions. This dissociation can affect the technological functionality of the milk concentrates. The present study aimed at determining the contribution of the gel layer deposited onto the membrane during filtration in the colloidal equilibrium between soluble and micellar caseins. Skimmed milk was concentrated by microfiltration combined with diafiltration using a cross-flow spiral-wound membrane at two transmembrane pressure (TMP) levels, causing differences in the extent of the gel layer formed. Non-sedimentable casein aggregates were formed to a greater extent at a low TMP compared to a high operating TMP. This difference was attributed to the greater compression of the deposit layer during filtration at a high TMP. This study contributes new knowledge to the understanding of how to modulate the functionality of milk concentrates through the control of processing conditions.

Effects of Drying Methods on Serum Protein Powder Properties

This study investigated the effects of atmospheric spray drying (ASD), low-pressure spray drying (LPSD) and freeze drying (FD) on the properties of serum protein powder, including the basic characteristics of the powder, bioactive proteins and changes in protein profile, using a proteomics approach. The total solid and water activity of the powder obtained by FD was significantly higher than that obtained by ASD and LPSD. There was no significant difference in the content of fat, lactose or solubility between the three kinds of powders. The concentration and activity of the proteins/enzymes in the serum protein powder made from LPSD were not altered after drying, similar to FD, although both parameters decreased after ASD. The microstructure of the powder observed by scanning electron microscopy indicated that the powder manufactured by ASD and LPSD was spherical in structure, while that manufactured by FD was flake-like. In total, there were 245 proteins identified in the serum protein concentrate and powder from the three drying methods. These findings indicate that LPSD is an effective and cost-saving method for producing serum whey protein powder.