Purple rice flour was modified using heat–moisture treatment (HMT) in three cycles using an oven (OHMT) and autoclave (AHMT) at temperatures of 100 °C and 120 °C, and with moisture levels of 20%, 25%, and 30%. X-ray diffraction was used to analyze the changes in the molecular structure. The swelling capacity, solubility, and starch digestibility, including rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), were studied in both native and modified purple rice flour. the bioactive compounds and antioxidant activities were also evaluated. Both OHMT and AHMT resulted in a decrease in swelling capacity, solubility, and RDS, but an increase in RS and SDS values compared to the native purple rice flour. All samples showed an increase in relative crystallinity. Both treatments also had an impact on the bioactive compounds and antioxidant activities, leading to a decrease in total phenolic content, total anthocyanin content, and the scavenging activity of DPPH and ABTS radicals compared to the native purple rice flour. The findings suggest that HMT can both improve the functional properties of purple rice flour and hold potential for use in various food industries.

Four types of traditional Thai rice—polished, black fragrant, glutinous and black glutinous rice—were separately used as raw material for vinegar production. During alcohol fermentation, using enriched baker’s dried yeast (S. cerevisiae) as a starter culture gave the highest ethanol content over 7 days of fermentation. The conversion of ethanol to acetic acid for vinegar production by Acetobacter pasteurianus TISTR 102 was performed for 25 days. The highest amount of acetic acid was detected with glutinous rice fermentation (6.68% w/v). The biological properties of Thai rice vinegars were determined, including the total phenolic content, antioxidant activity, antibacterial activity and cytotoxicity. Black glutinous rice vinegar exhibited the maximum total phenolic content of 133.68 mg GAE/100 mL. This result was related to the antioxidative activity findings, for which black glutinous rice vinegar exhibited the strongest activity against both ABTS^•+ and DPPH^• radicals. Cytotoxicity against the human colon cancer cell line (HT-29) provided an IC₅₀ value of 74.02 μg/mL and weak activity in a mouse fibroblast normal cell line (L929) with an IC₅₀ value of 171.06 μg/mL. Glutinous rice vinegar was the most effective vinegar for inhibiting pathogenic bacterial growth of both Gram-negative and Gram-positive bacteria. These results suggested that the value of total phenolic content corresponded to the anticancer activity and antioxidant activity results, while antibacterial activity depended on the acidity of rice vinegar.

Essential oils from the aerial parts of four Elsholtzia species; Elsholtzia stachyodes, Elsholtzia communis, Elsholtzia griffithii and Elsholtzia beddomei were obtained by steam distillation and their chemical components were analysed by gas chromatography-mass spectrometry (GC-MS). Principle Component Analysis was used to identify the chemical variations in the essential oils from these plants, which could be categorised into two groups according to their main chemical components which are acylfuran derivatives and oxygenated monoterpenes. Additionally, the anti-acne inducing bacterial activity against Staphylococcus aureus and Staphylococcus epidermidis were evaluated. The oil from E. stachyodes was the most efficacious against the growth of S. aureus and S. epidermidis having MIC values of 0.78 and 1.56 μL/mL, respectively, and exhibited five times more effective than erythromycin (standard antibiotic).

Purple rice (Oryza sativa L.) is a pigmented plant-based food whose starch is rich in the anthocyanins cyanidin-3-glucoside (C3G) and peonidin-3-glucoside (P3G), yet is largely rapidly digestible and confers a high glycemic index that limits its dietary use. Converting native starch into resistant starch type III (RS3) via dual autoclav-ing-retrogradation treatment (DART) or dual enzyme treatment (DET) lowers digesti-bility, but the conditions required compromise anthocyanin stability. This study tracked how these two food-processing routes govern phenolic and anthocyanin fate, structure and digestibility. RS3 content rose from 5.35% (native) to 34.13% (DART) and 51.34% (DET), while total phenolic content fell by 76.1% and 71.4% and the starch darkened (L* 68.27 to 43.49 and 28.25); free C3G became undetectable after DART but was partly retained (11.86 mg/100 g) after DET. X-ray diffraction showed A-type to B-type conversion after DART, whereas DET gave a mixed B+V-type pattern with a diagnostic peak near 2θ ≈ 19°, coinciding with greater phenolic retention. Both RS3 products resisted simulated digestion, with DET-RS3 limiting intestinal hydrolysis to 12.72% versus 30.71% for native starch. Processing thus entails a nutritional trade-off, partly offset in DET by amylose-phenolic complexation, positioning purple-rice RS3 as a candidate colon-targeted antioxidant delivery vehicle.