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Different sources of Dioscorea nipponica Makino. were collected from different regions, Funiu, Qingyuan, and Yichun. Starches isolated from the three sources were studied regarding their morphological, physicochemical, and thermal properties. Funiu and Qingyuan starches have larger granules than Yichun starch. The swelling power (85–95°C), solubility (85–95°C), amylose leaching, moisture content, protein content, and starch content were found to be higher compared to the Yichun starch. However, the Yichun starch displayed much higher gelatinization temperatures and enthalpy of gelatinization (ΔHgel) (1.69 J/g), meanwhile Funiu starch presented the lowest values (0.55 J/g). To, Tp, and Tc values varied from 68.41 to 71.96°C, 73.83 to 77.76°C, and 78.92 to 82.52°C, respectively. Funiu starch with higher digestibility was more susceptible to in vitro starch digestibility than Qingyuan and Yichun starches after 40–180 min, which provided more information about the starch nutritional component.

Traditional Chinese medicines (TCMs), Paeonia suffruticosa Andr. (PSA), Paeonia lactiflora Pall. (PLP), and Curcuma phaeocaulis Val. (CPV) all contained abundant starch in tubers, which have usually been discard as waste in the pharmaceutical industry. In this paper, the intrinsic properties of three TCM starches were studied and the structure–property relationships were analyzed, on the purpose of exploring new starch resource for food and non-food industries. PSA starch with the highest amylose (AM) content showed the lowest water binding capacity (WBC), while the CPV starch showed the contrary. Moreover, the starches differed in granule shape and size. The PSA and PLP starches had larger spherical or elliptic granules, whereas CPV starch possessed the smallest granules in large number among the three starches. PSA starch displayed the typical C-type diffraction pattern, while the PLP and CPV starches were classified as A-type pattern. The degrees of crystallinity of the three TCM starches were about 22.8, 16.6, and 24.2%, respectively. The starch separated from CPV indicated the highest transition temperatures (To, Tp, and Tc) and gelatinization temperature range (R) value with lowest peak height indices (PHI), whereas PLP starch showed the lowest transition temperatures and enthalpy of gelatinization (ΔHgel).

The effect of sulfur fumigation and freeze–drying on the physicochemical and functional properties of Dioscorea opposita Thunb. starch was investigated. Freeze–drying markedly decreased the AM content of starch from 16.68 to 8.59%. Both sulfur fumigation and freeze–drying decreased the protein content but obviously increased the water absorption capacity and swelling power. Sulfur fumigation significantly increased the solubility of starch. Retrogradation tests showed that Chinese yam starch had a poor stability of retrogradation in water, salty, sugar, and acidic medium, but a good stability in alkaline medium. SEM analysis showed that different drying methods had minor effects on the morphological properties of D. opposita cv. Ma starch. Although the pattern of D. opposita cv. Ma starch was C-type and was not affected by drying methods, sulfur-fumigation, and freeze–drying increased the crystalline degree of starches from 23.24 to 25.16% and 34.40%, respectively. A minor difference was found in the Fourier transform infrared spectra of native and treatment starches. After sulfur fumigation and freeze–drying, the peak gelatinization temperatures increased from 71.03 to 76.03°C and 83.07°C, respectively, whereas the gelatinization enthalpy and gelatinization range decreased.

Starches isolated from the bulbs of Pueraria lobata (Willd.) Ohwi (PLO) and Pueraria thomsonii Benth. (PTB) were hydrolysed by glucoamylase for different lengths of time (2, 4, 8, 12, and 24 h). The hydrolysis results were compared by scanning electron microscope (SEM), X-ray power diffractometer (XRD), and differential scanning calorimetry (DSC). The SEM results revealed that both of the PLO and PTB starches showed the same hydrolysis mechanism, which indicated that the glucoamylase primarily attacking the exterior of starch granules and then the interior. The results of XRD revealed the crystalline type of PTB starch changed from C-type to A-type with crystallinity reducing from 43.5 to 20.9% during the hydrolysis. Unlike PTB starch, the PLO starch did not show marked changes in crystalline style but lower degree of crystallinity was obtained from 32.4 to 13.7% during the hydrolysis. All the XRD results demonstrated that B-type polymorph was preferentially degraded than A-type polymorph in the C-type starch. The DSC results revealed that both of the PLO and PTB starches showed decreased enthalpy of gelatinization (ΔHgel) and gelatinization temperature range (R)-value after hydrolysis, while the gelatinization temperature (Tp) indicated different tendency, initially ranging from 68.6 to 64.3°C and then increasing to 67.8°C for PLO starch. While for PTB starch, the Tp-value showed progressive reduction from 85.4 to 74.3°C during the whole process.

Dioscorea alata Linn. (D. AL) rich in starch was widely used as food and medicine. This work aimed to compare the effect of acid and glucoamylase on the starch of different reaction time. The physicochemical properties of the native and hydrolyzed starches, such as swelling power (SP), starch solubility (SOL), and paste clarity were also determined in this study. The native and modified starches by acid and glucoamylase were compared and characterized by scanning electron microscope (SEM) and secondary derivative FT-IR spectroscopy. The morphological characteristics of native D. AL starch granules revealed by SEM varied from round to oval or elliptic with smooth surface. SEM showed that glucoamylase primarily attacked the exterior of starch granules and permeate into the interior by the cracks formed on the surface. Owing to acid hydrolysis, the starch granules were depressed and transformed to bread-like in shape and then broke into irregular lumps with particles adhered. From secondary derivative FT-IR spectrum, the intensities of the two peaks from acid and enzyme hydrolysis starches at 1137 and 1066/cm were stronger than native starch. Some new peaks appeared due to hydrolysis. The digested starches exhibited a lower SOL and SP than native starch in water as the temperature increasing. The light transmittance of the digested starches was significantly higher than that of native starch paste and decreased with increase in storage period.

The starches separated from bulbs of four different lily cultivars (Lanzhou, Pinglu, Yixing-1, and Yixing-2) were investigated for physicochemical, morphological, crystalline, and thermal properties. AM content of lily bulbs starches from different cultivars ranged from 19.46 to 25.17%. The swelling power of starches ranged between 14.4 and 21.3 g/g, and the solubility ranged from 8.92 and 16.6% at the temperature of 85°C. Four cultivars of lily starches paste had excellent transparency and the transmittance value of Lanzhou lily as high as 54.7%. The transmittance of the gelatinized aqueous starch suspensions, from all lily cultivars, decreased with increase in storage period. The shape of starch granules varied from triangular to cylindrical and XRD of four lily starches all showed B-type pattern. The transition temperatures and enthalpy of gelatinization (ΔHgel) were determined using DSC. Tp varied from 62.52 to 65.25°C. Pinglu lily starch showed the highest ΔHgel and gelatinization range (Tc–To) index among starches from four different lily cultivars.

The starches studied from the nine Fritillaria species had differently shaped and sized granules but all of them showed the presence of smooth, round, or elliptic-shaped, indicating that the isolation process did not destroyed the starch granules. The nine Fritillaria starches presented different AM content, moisture content, ash content, particle size, swelling power, solubility, water absorption capacity and light transmittance. The starches isolated from Chuan-Beimu species exhibited a higher amount of crude protein content and lower amount of AM than other the groups, which had lower swelling power, higher solubility and light transmittance. All the nine Fritillaria starches had an XRD pattern of the B-type. In addition, F. hupehensis, F. walujewii and F. ussuriensis starches with fairly large-sized or irregular granules had higher Tp and ΔHgel values than that isolated from the four Chuan-Beimu species. The results obtained yielded information about the possible behavior of these starches when being used in certain applications. Cluster analysis results showed that this classification method based on macromolecule chemical compounds (starch) is original and credible in the quality control of various Beimu. In addition, it provided more information to the authentication systematics taxonomy methods including morphological, histological and molecular biological techniques of Fritillaria species.

The physico‐chemical, morphological, thermal, and crystal properties of the starches separated from three different rhizomes of Dioscorea bulbifera Linn. (D.BLH, Hubei; D.BLG1, Guangxitianlin; D.BLG2, Guangxiyulin) were studied and compared. A light microscopic technique was applied in order to quantify the integrity and shape of the starch granules after isolation. Amylose contents of different cultivars were in the range of 12.18–14.34%. Moisture content, ash content, swelling power, solubility, water‐binding capacity, and protein content of starches also differed significantly. The three different D. bulbifera starches all showed a typical C‐type pattern with crystallinity 45.36, 27.10, and 53.04%, corresponding to D.BLH, D.BLG1, and D.BLG2, respectively. The starch separated from the three starches above showed gelatinization range of 10.09, 11.55, and 7.26°C, corresponding to D.BLH, D.BLG1, and D.BLG2. The enthalpy of gelatinization (I”Hgel) ranged from 1.28 to 3.11 J/g. Correlation analysis displayed that amylose content and relative crystallinity values were important in determining thermal starches.

Aconitum, an important toxic traditional Chinese medicine, has been widely used in clinical practice. Owing to its toxicity, it should be processed before application. Aconiti lateralis Preparata (ALP) is one of the most important commercial processed products of Aconitum. The object of this work is to study the physicochemical and functional properties of Aconitum and ALP starches. The results revealed that AM content changed, transforming from 37.5 to 27.5% after processing. The shape of Aconitum starch granules also changed from spherical or oval with sizes of 5–15 µm to irregular and polygonal with sizes of 30–60 µm. The crystallinity of Aconitum decreased from 38.7 to 23.0% after processing. The transition temperatures (To, Tp and Tc) and enthalpy of gelatinization (ΔHgel) were determined using DSC. To, Tp and Tc decreased from 52.9 to 48.6, 66.9 to 58.9, and 82.2 to 69.3°C, respectively. Aconitum starch showed higher ΔHgel values (1.6 J/g), while the ALP starch showed lower values (0.4 J/g).

As a source of starch, Pueraria thomsonii Benth. was selected to synthesize carboxymethyl starch (CMS) with monochloroacetic acid (MCA) in the presence of sodium hydroxide for the first time. The influence of the molar ratio of NaOH/AGU and MCA/AGU, reaction time, temperature, and water content of solvent on the degree of substitution and reaction efficiency were studied. IR spectrometry showed bands at 1609, 1420, and 1369 cm−1 due to –COO− symmetric and asymmetric stretching vibration when starch was successfully substituted. The SEM results displayed that the granules were agglomerate, and curly wrinkles appeared upon carboxymethylation. XRD revealed that the crystallinity reduced from 41.45 to 5.91%. Furthermore, the 13C NMR spectra of the CMS showed a broad band at d = 178.85 ppm, which was assigned to the –CO carbon (C-8) of the carboxymethyl group.

Starch extracted from Chinese yam was characterized by scanning electron microscope (SEM), X-ray powder diffractometer (XRD), and differential scanning calorimeter (DSC) in the process of enzymatic hydrolysis. Yam starch was digested by α-amylase and gluco-amylase for different lengths of time, respectively, and two different enzymatic hydrolysis results were compared. The most notable phenomenon revealed by SEM after α-amylase hydrolysis was the formation of the cavum in the center of the starch granules, while after gluco-amylase hydrolysis, the outer layer of the granules was peeled off and then some granules even broke into pieces. The XRD of the two enzyme hydrolyzed starches revealed the crystal type of the starch changed from typical C-type XRD pattern to the representative A-type pattern in the process of enzymatic hydrolysis. The above results also demonstrated that the partially B-type polymorph was more easily degraded than A-type. The thermal result showed that the modified yam starches by both enzymes exhibited increased peak gelatinization temperatures (Tp) and decreased gelatinization enthalpy (ΔH).