Determination of organic acid impurities in lactic acid obtained by fermentation of sugarcane juice

Formation of Volatile and Aroma Compounds during the Dehydration of Membrane-Clarified Sugarcane Juice to Non-Centrifugal Sugar

The development of volatile compounds and their precursors during the dehydration process of membrane-clarified sugarcane juice to non-centrifugal sugar (NCS) was investigated. Head-space solid phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS) coupled with chemometrics was employed to assess the differences at the various stages of the dehydration process. A total of 111 volatile compounds were identified, among which 57 were endogenous compounds from sugarcane juice and displayed an attenuated abundance in the first 30 min. Typical oxygen and nitrogen heterocyclic compounds, including furans and pyrazines, and aldehydes derived were found to be the main volatiles contributing to the formation of NCS characteristic aroma, with phenols, alcohols, esters, acids, and sulfur compounds as supplementary odor. Free amino acids and reducing sugars were identified as important precursors for the aroma development process. The low temperature (90–108 °C) and micro vacuum condition (−0.03 MPa) approach used in this study could be an alternative option for the manufacture of NCS.

Progress in pretreatment and analysis of organic Acids: An update since 2010

Organic acids, as an important component of food, have great influence on the flavor, texture, freshness of food. By lowering the pH of food to bacteriostatic acidity, organic acids are also used as additives and preservatives. Because organic acids are crucial to predict and evaluate food maturity, production and quality control, the rapid and sensitive determination methods of organic acids are necessary. This review aims to summarize and update the progress of the determination of organic acids in food samples. Pretreatment methods include simple steps (e.g., "dilute and shoot," protein precipitation, filtration, and centrifugation) and advanced microextraction methods (e.g., hollow fiber liquid phase microextraction, stir bar sorptive extraction and dispersive micro-solid phase extraction). Advances in novel materials (nanomaterial), solvents (ionic liquids and supercritical fluids) and hybrid methods are clearly displayed in detail. Continuous progress which has been made in electrochemical method, two-dimensional chromatography, high resolution mass is thoroughly illustrated.

Sustainable Processes and Chemical Characterization of Natural Food Additives: Palmyra Palm (Borassus Flabellifer Linn.) Granulated Sugar

Palmyra palm (Borassus flabellifer Linn.) is an important sugar-producing plant that is widely distributed in tropical Asian countries. Its jaggery and sweet sap are prevalent in Cambodia as a substitute for table sugar. They contain essential minerals, vitamins, and biological compounds. We investigated the changes in the nutritional composition, antioxidant properties, and biological activity of palm granulated sugar prepared by using three different drying–solidification processes under vacuum conditions: the drying temperature was controlled at 80 °C, 90 °C, and 100 °C, and the drying time was 60, 75, and 90 min, respectively. Palm granulated sugar contains 10 kinds of vitamins (mainly vitamin E 52.15–55.12 mg/100 g), 5-hydroxymethylfurfural (2.18 to 41.92 mg/100 g), and 38 volatile compounds that belong to the alcohol, ketones, pyrazines, acids, and phenols groups, and an aldehyde group. Moreover, palm granulated sugar exhibits a high total phenolic content (2.77–8.94 mg gallic acid equivalent/100 g), 2,2-diphenyl-1-1picrylhydrazyl (DPPH) radical scavenging activity (20.15%–37.88%), and ferric reducing antioxidant power (FRAP) value (322.68–378.23 μmol Fe2+/mL). Furthermore, palm granulated sugar-treated NIH3T3 cells showed a higher cell viability of 18.10% to 23.68%. This study confirmed that palm granulated sugar prepared at 90 °C for 75 min can have a better product quality with increased vitamin and mineral contents, antioxidant properties, and biological activity, while also being low in 5-hydroxymethylfurfural (HMF) content.

Comparative study of the physicochemical, nutritional, and antioxidant properties of some commercial refined and non-centrifugal sugars

Three refined and four unrefined branded commercial sugars available in Korea were investigated in terms of pH, soluble solids, moisture, ash content, turbidity, color values, microbial profile, reducing power, 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities, cellular antioxidant activity, and total phytoconstituent (i.e. phenolic, flavonoid, mineral, sucrose, glucose, and fructose) contents using standard analytical protocols such as high-performance liquid chromatography, gas chromatography-flame ionization detector/mass spectrometry, and inductively coupled plasma atomic emission spectroscopy. All tested physicochemical parameters were within the recommended standard levels. Significantly high nutritional and antioxidant properties were observed for the unrefined sugars, especially AUNO® sugar, whereas a high sucrose content was detected for the refined sugars. Hence, this study revealed that the degree of purification affects the nutritional values and antioxidant potentials of sugars. The present findings also indicate that unrefined sugars can be used as sweeteners in sugar-based cuisine to obtain nutritional and antioxidant-rich foodstuff.

Gas Chromatographic Method for the Analysis of Organic Acids in the Bio-Catalytic Conversion Process

An analytical method for the quantification of acrylic acid (AA), 1,3-propanediol (1,3-PD) and 3-hydroxypropionic acid (3-HP) in the bio-catalytic conversion process has been developed by gas chromatography. A simple liquid-liquid extraction (LLE) procedure was used in the sample preparation. Organic acid additives such as trifluoroacetic acid were used to improve the extraction efficiency in the LLE procedure. Under optimum analysis conditions, all analytes were satisfactorily separated with no interference. In standard calibration, all correlation coefficients (r(2)) were better than or equal to 0.994. In culture media, the intra-batch precision (% relative standard deviation) and recovery (%) as the average value of the quality control samples were 2.3 and 102.4%, respectively. In addition, the inter-batch precision and recovery as the average value of the quality control samples were 5.0 and 104.0%, respectively. In phosphate buffer, the intra-batch precision and recovery as the average value of the quality control samples were 2.7 and 101.6%, respectively. In addition, the inter-batch precision and recovery as the average value of the quality control samples were 2.9 and 101.7%, respectively. The limit of detection (S/N ratio: 3) and limit of quantification (S/N ratio: 10) were 1.0 and 3.5 µg/mL, 3.0 and 10.0 µg/mL, and 9.0 and 30.0 µg/mL, respectively, for AA, 1,3-PD and 3-HP. Consequently, this method was demonstrated to be acceptable for the quantitative analysis of AA, 1,3-PD and 3-HP in culture media and phosphate buffer.