In this paper, apple crispness was evaluated by sensory evaluation and compared with non-destructive measurements of portable acoustic signal to discuss the feasibility of non-destructive evaluation for apple crispness based on portable acoustic signal. Acoustic eigenvalues from the acoustic signal were processed by time domain and Hilbert-Huang transform (HHT), followed by analysing the correlations with apple crispness that had been evaluated via sensory evaluation. Multiple linear regression (MLR) and artificial neural network (ANN) were applied to predict apple crispness. The results proved that crispness correlates significantly (P < 0.01) with four acoustic eigenvalues, including waveform index, sound intensity, energy of low frequency and energy of high frequency. The average relative error of apple crispness predicted by ANN was 1.42 AE 1.9%, remarkably lower (P < 0.01) that of MLR (6.79 AE 5.64%), implying that the model predicted by ANN is more accurate than that of MLR.

Sagittaria trifolia tuber is an aquatic vegetable. In this work, microwave‐assisted enzymatic extraction (MEE) was used to extract S. trifolia tuber polysaccharides (STTPs). Optimum conditions were complex enzyme of 2 %, liquid‐to‐solid ratio of 43 : 1 mL g−1, microwave power of 506 W, and time of 8 min, under which STTPs yield was 36.22±0.69 %, higher than those of other methods. STTPs were sulfated polysaccharides with sulfur valence of S6+. STTPs comprised mannose, glucose, galactose, and arabinose at a mole ratio of 3.69 : 19.33 : 6.21 : 1.00, molecular weights of 3606 kDa and 149.6 kDa, particle size of 220 nm, and zeta potential of −5.02 mV. The surface of STTPs was full of bumps and holes, and abundant in O1s and non‐functionalized C1s. STTPs would scavenge reactive oxygen species with advantage. It would provide an efficient MEE method to obtain antioxidant STTPs, also a clue for extracting polysaccharides from starch‐rich crops.

Unconventional polysaccharides as representative active substances from stems of Trollius chinensis Bunge (TC) were studied. Crude polysaccharides from the stems of TC (TCSP) and the petals of TC (TCPP) were extracted, and the moisture retention and antioxidation activities of both TCSP and TCPP in vitro were studied. The weight-average molar masses (Mw) of TCSP (6.07 × 105 Da) were lower than those of TCPP (9.72 × 105 Da). Glucuronic acid and xylose only existed in TCSP, and the molar ratio of galacturonic acid and mannose in TCSP was significantly higher than that in TCPP. No significant differences in moisture retention ability were found between TCSP and TCPP. The reducing capacity and dphenyl picryl hydrazinyl (DPPH) radical scavenging capacity of TCSP were slightly weaker than those of TCPP. The 2,2-azino-bis (3-ethylbenzothiazoline–6-sulfonic acid) (ABTS) radical scavenging capacity of TCSP can be equivalent to that of TCPP. The moisture retention ability was not different between TCSP and TCPP, which are both highly homologous with traditional humectants. The antioxidation assays in vitro demonstrated that the antioxidant activity of TCSP is stronger compared to that of some plant-derived polysaccharides. The stems of TC can be a promising source of unconventional polysaccharides, which possess moisture retention and antioxidation capacities for the cosmetics industry.

In this article, the synergistic effect in moisturizing activity and antioxidant activity between the promising unconventional polysaccharide and flavonoids from stems of Trollius chinensis bunge (TCS) was investigated. The results showed that the mixture with the mass ratio (w/w) of 7:3 (flavonoids to polysaccharides) appeared better moisture retention (73.08 ± 2.4%) and scavenging effects on·OH radicals (85.46 ± 0.52%). Meanwhile, the mixture with the mass ratio (w/w) of 3:7 (flavonoids to polysaccharides) unveiled better scavenging effects on DPPH radicals (44.10 ± 0.81%) and reducing capacity. The results confirmed that the polysaccharides and flavonoids from TCS have good synergistic effects in moisturizing activity and antioxidant activity, and have the potential to be used in the food industry as edible films or edible packaging materials.