Smart PTFE Membrane with Hydrophilicity and pH Sensitivity through MAA-grafting

In this article, the microporous membrane of stretched polytetrafluoroethylene (S-PTFE) film was modified through grafting hydrophilic methacrylic acid (MAA). SEM image showed that the grafted poly(methacrylic acid) (PMAA) covered uniquely on regular nanofiber-frame in S-PTFE. The surface contact angle of the membrane minishes rapidly with the increase of grafting ratio and falls down to the minimum point at 57° when the grafting ratio is about 4.7%. The water flux of the PTFE-g-PMAA membrane is very sensitive to pH values. At lower pH, the larger water flux was obtained. This contribution indicate the possibility of adjustable water flux by pH.     

Preparation of liquid-core hydrogel beads using antioxidant-rich Syzygium caryophyllatum fruit pulp as a healthy snack

Reverse spherification is a common technique used in molecular gastronomy to produce innovative products with an improved texture by shaping a liquid into an edible semisolid sphere that gives a burst in the mouth sensation. In this study, liquid-core hydrogel beads (LHBs) were prepared using Syzygium caryophyllatum fruit pulp adapting reverse-phase molecular gastronomy as a minimal processing technique to promote it as a healthy snack. Three types of hydrogel beads were formulated while considering the stability of LHBs. Long-term hardening of fruit juice in sodium alginate solution and the addition of plasticizer was used as two methods to increase the textural stability of LHBs. Results revealed that the addition of the plasticizer imparted to improve all the physical and textural properties of beads; however, it affects the transparency of the hydrogel membrane as well. Although the plasticizer increased the textural stability of LHBs, prolong inlaying them in it (the plasticizer) contribute to occur adverse consequences on the quality. Hence, the inlaying of LHBs in glycerol for 2 min was selected as the best treatment (HBP1). Since HBP1 had a low hardness (125.00 g) and high resilience (0.21), it imparted a chewing gum-like texture to LHBs. Hence, it (HBP1) can be used as a healthy snack. While HBP1 was capable of retained 90% antioxidant activity of fresh fruit of S. caryophyllatum, total polyphenolic content, 2,2-diphenyl-2-picryl-hydrazyl scavenging activity %, and ferric reducing antioxidant power value of this formulation were 59.50 GAE/g of dried LHBs, 68.96% and 139.69 TE/g of dried LHBs, respectively.