Formation mechanism and stability of low environment-sensitive ternary nanoparticles based on zein-pea protein-pectin for astaxanthin delivery

This study was devoted for preparing zein-pea protein-pectin ternary nanoparticles through an alcohol-free pH-shifting method for the delivery of astaxanthin(Ax).The complexation of zein and pea protein(PP)in the weight ratio range of 1:2.5 to 1.2:1 maintained the dispersity at pH 7.0 with the average particle size of 90.47-132.38 nm and the polydispersity index of 0.204-0.245.The circular dichroism,fluorescence,Fourier transform infrared spectroscopy and other analyses indicated that the zein interacted with PP to form a composite structure through the folding action of protein structure in the process of pH reduction driven by hydrophobic and electrostatic forces.The incorporation of pectin(pec)further enhanced the physicochemical stability of the nanoparticles.The optimal weight ratio of zein/PP/pec was 2:4:3,and the encapsulation efficiency of astaxanthin reached 94.22%.The X-ray diffraction results showed that the astaxanthin was amorphous after embedding.Compared with Ax/zein-PP,the Ax/zein-PP-pec showed better colloidal stability under the conditions of wide pH range(4.0-8.0),high temperature(90℃),long time ultraviolet light treatment,and 15-day storage.These results indicated that the construction of the zein-PP-pec nanoparticles could be used as a low environment-sensitive nanocarrier for the loading,protection,and delivery of hydrophobic functional substances such as astaxanthin.

Microwave heating and conduction heating pork belly: Influence of heat transfer modes on volatile compounds and aroma attributes

This work was conducted to compare the differences in odor attributes and the formation causes of pork belly cooked by different heating modes and the feasibility of achieving convenient and delicious cooking of stir-fried pork cuisines by modifying the heat transfer mode of the microwave.The effects of traditional pan-heating(TH),microwave heating(MH),and microwave combined with conduction heating(MH+CH)on sensory aroma attributes,aroma profile,free fatty acids,and volatile compounds of pork belly were investigated.The results showed that the pork belly heated by TH had the lowest total amount of stable volatile compounds(1695.41μg/kg)and contents of free fatty acids(751.44 mg/100g),but the balanced distribution and the rich contents of volatile compounds derived from thermal processing resulted in the better aroma quality of pork belly.In contrast,although the pork belly cooked by MH had higher free fatty acids contents(1215.32 mg/100g)and the highest volatile compounds(5410.56μg/kg),due to the cell destruction effect and the molecular movement acceleration of microwave,the contents of volatile compounds derived from spices were too high,leading to the disharmony of aroma characteristics.However,the pork belly cooked with MH+CH not only promoted the production of free fatty acids(1434.23 mg/100g),but also increased the generation and retention of pork characteristic aroma by changing the heating modes.Compared with MH,it enhanced the uniformity of aroma distribution and improved the overall aroma similarity to TH.