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Water caltrop has a high starch content and is a promising resource of starch in Asia. Starch can be divided into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS). Here, the effects of physical modification by microwave treatments, heat–moisture treatments, and pressure–heat treatments on the physiochemical and structural properties and on the in vitro digestibility of water caltrop starch is studied. The results show that, compared with native starch (NS), the solubility and swelling power of modified starch samples decrease with prolonged microwave and heat–moisture treatment. The infrared absorbance ratio at 1047 cm−1/1022 cm−1 is decreased in starch samples modified by microwave treatment and pressure–heat treatment, the NS samples present a C‐type crystalline pattern which changes into an A‐type pattern upon microwave treatment. Water caltrop starch subjected to 50 s of microwave treatment has the highest amylose (48.78%), the highest crystallinity (42.95%), and the highest RS content (67.41%, uncooked and 48.91%, cooked). Water caltrop starch subjected to 3 h of heat–moisture treatment contains the highest SDS content (54.33%, uncooked and 60.11%, cooked).

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Termitomyces albuminosus (termite mushroom) is an edible fungus growing from termitaries in certain parts of China. Recently, the mushroom has gained in popularity, but due to rapid post-harvest quality decay, novel processing techniques including drying are required. This study aimed to optimize the conditions of combined microwave and hot air drying for T. albuminosus. Factors including microwave density, air temperature, and moisture content at conversion point were investigated and optimized using the drying rate, protein content, color L*, DPPH scavenging ability, rehydration ratio (RR), texture, sensory, and overall score as responses. The results showed that the overall score dried at 1.83 W/g microwave density, 60°C hot air, and 50% moisture content at conversion point were 0.675, 0.575, 0.530, respectively.The optimum conditions of combined microwave and hot air drying were microwave density 2.0 W/g, moisture content 52% at conversion point, and hot air temperature 57 respectively. The optimum conditions of combined microwave and hot air drying L* was 54.16, DPPH clearance was 91.87%, RR was 2.41, pileus chewiness was 1,587.19 g, stipe chewiness was 4,457.28 g, sensory score was 7.3, and overall score was 0.793, while the sensory quality was very high. Therefore, microwave drying followed by hot air drying is an effective, suitable method to obtain dried T. albuminosus.

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The effect of high-pressure cooking processing (HPCP) on the physicochemical structure and in vitro digestion of citric acid-esterified starches made from different materials (water chestnut, sweet potato, potato, corn) was investigated. HPCP increased the swelling and solubility of sweet potato esterified starch (SPSC) and potato esterified starch (PSC) and decreased the swelling and solubility of water chestnut esterified starch (WCSC) and corn esterified starch (CSC). Fourier-transform infrared spectroscopy revealed that the short-range structure of starches was more orderly. Differential scanning calorimetry and X-ray diffraction were used to determine the crystallisation peaks and enthalpy of different starches after HPCP. HPCP decreased the SPSC and PSC content of resistant starches (RS). However, HPCP showed no significant effect on the RS and estimated glycaemic index of WCSC and CSC. The results showed that the RS in WCSC and CSC had stronger thermal stability and was more suitable to be added to heat-processed foods.

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