Methenamine Hippurate

One of the most common types of adulteration of honey involves the addition of invert sugar syrups. A new method was developed to measure the stable isotope ratios of carbon and carbon-bound non-exchangeable (CBNE) hydrogen from specific molecular positions in fructose and glucose in honey. This was achieved through periodate oxidation of the sugars to produce formaldehyde, followed by reaction with ammonia to form hexamethylenetetramine (HMT). The preparation was simplified, optimized, and validated by isotopic analysis of replicate syntheses of HMT from fructose, glucose, sugar syrup and a representative authentic honey sample. The optimized method had a repeatability standard deviation from 1.5‰ to 3.0‰ and from 0.1‰ to 0.4‰ for δ²H and δ¹³C, respectively. This methodology has advantages over alternative isotopic methods, for measuring CBNE hydrogen isotope ratios in sugars, in terms of time, sensitivity and operability and offers a complementary method to differentiate authentic honey from invert sugar syrups.

The advantages of physically modifying starch are evident: minimal environmental impact, no by-products, and straightforward control. The impact of dual modification on starch properties is contingent upon modification conditions and starch type. Herein, we subjected purple rice starch (PRS) to heat-moisture treatment (HMT, 110 °C, 4 h) with varying moisture content, ultrasound treatment (UT, 50 Hz, 30 min) with different ultrasonic power, and a combination of HMT and UT. Our findings reveal that UT following HMT dispersed starch granules initially aggregated by HMT and resulted in a rougher granule surface. Rheological analysis showcased a synergistic effect of HMT and UT, enhancing the fluidity of PRS and reinforcing its resistance to deformation in paste form. The absorbance ratio R_1047/1015 indicates that increased moisture content during HMT and high ultrasound power for UT reduced the short-range order degree (1.69). However, the combined HMT-UT exhibited an increased R_1047/1015 (1.38-1.64) compared to HMT alone (1.29-1.45), likely due to short-chain rearrangement. Notably, the A-type structure of PRS remained unaltered, but overall crystallinity significantly decreased (23.01 %-28.56 %), consistent with DSC results. In summary, physical modifications exerted significant effects on PRS, shedding light on the mechanisms governing the transformation of structural properties during HMT-UT.