Ultrasonic (US) treatment was combined with pH shifting (pHS) and mild thermal (40 °C) (T40) treatment (US/T40/pHS) to improve the solubility of potato protein. The effects of the ultrasonication frequency, ultrasonication time, and incorporation sequence on the solubility of potato protein were investigated. The results showed that online US/T40/pHS treatment resulted in higher solubility of potato protein and enhanced free amino group release during in vitro digestion. The solubility of potato protein treated with online US/T40/pHS at a mono-frequency of 40 kHz for 15 min increased by 1.73 times compared with the control (p < 0.05). The digestibility rate increased by 16.0% and 30.8% during gastric and intestinal digestion, respectively, compared with the control (p < 0.05). It was demonstrated that online US/T40/pHS treatment significantly changed the secondary and tertiary structures of potato protein according to the results of circular dichroism and internal fluorescence. SDS-PAGE, particle size, and atomic force microscopy (AFM) showed that structural changes led to the formation of large soluble aggregates. The results suggested that the improvement in the solubility and digestibility of potato protein treated with online US/T40/pHS may be due to the formation of large soluble aggregates, which are more hydrophilic and sensitive to digestive enzymes.

Incorporating protein emulsified droplets into protein gels as the active fillers have attracted much attention. However, using animal and plant protein mixtures emulsified droplets as the filler is lacked. The...

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Directly using cheap D,L-lactic acid (D,L-LA) and glucose (Glu) as starting materials, biodegradable material poly(D,L-lactic acid-co-Glucose) [P(D,L-LA-co-Glu)] was synthesized via melt polycondensation. When n(Glu) : n(D,L-LA) = 1:200, the appropriate synthetic condition is that: after 120 °C prepolymerization for 5 h, 160 °C melt polymerization catalyzed by w(SnCl2) = 0.5% for 5 h. P(D,L-LA-co-Glu) with different molar feed ratios were synthesized and characterized with [η], FTIR, 1H NMR, GPC and XRD. The Tg of all copolymer P(D,L-LA-co-Glu) was lower than that of homopolymer polylactic acid directly synthesized via melt polycondensation. The copolymers with Mw from 2,100 Da to 5,100 Da could meet the demand of drug delivery carrier material.

Principal component analysis (PCA) was used to cluster the possible amino acid compositions of antioxidant peptides in potato protein hydrolysate (PPH). The antioxidant peptides exhibiting high ABTS+• scavenging capacity were isolated with the procedure of ultrafiltration, gel filtration, and preparative RP-HPLC and identified by UPLC-MS/MS. Phe, Tyr, and His were shown to group together with ABTS+• scavenging capacity in component matrix plot. Three prominent peptides, namely, Phe-Tyr, Tyr-Phe-Glu, and Pro-Pro-His-Tyr-Phe, which matched the sequence of patatin and were made up of Phe and Tyr, were identified. The peptide Tyr-Phe-Glu demonstrated antioxidant activity against Caco-2 cell oxidation induced by H2O2. The results suggested that multivariate analysis could be used to predict the amino acid compositions of antioxidant peptides.

Using 1,3,5-benzenetrioxyundecanol (mTU) as the core, and L-lactic acid (L-LA) as starting material, a novel star-shaped poly(L-lactic acid) (SPLLA) was synthesized via direct melt polycondensation with simple process and low-cost. The obtained biodegradable polymer SPLLA was systematically characterized with the intrinsic viscosity [η], FTIR, 1H-NMR, GPC and XRD. The Mw, Tg, Tm, ΔH, crystallinity, crystallite size of all SPLLA basically increased with the increase of the molar feed ratio n(L-LA) : n(mTU). When n(L-LA) : n(mTU) was 500:1, the biggest Mw was 8600, but all Mw meet the requirement for drug delivery application.