Formation of 5-hydroxymethylfurfural in industrial-scale apple juice concentrate processing

Fabrication of thermotolerant ovalbumin and carboxymethyl starch sodium complexed nanoparticles and high-internal-phase Pickering emulsion for food chemical hazards inhibition

Protein/polysaccharide nanoparticle-stabilized Pickering high-internal-phase emulsions (HIPEs) can be customized to reduce foodborne hazards and enhance food quality. However, preparing thermostable HIPEs remains challenging. This study developed thermally stable OCCNPs-stabilized HIPEs by modulating the interactions between ovalbumin (OVA) and sodium carboxymethyl starch (CMSNa) to fabricate nanoparticles (OCCNPs). The results showed OCCNPs with a particle size of 378.6 nm were successfully prepared with a three-phase contact angle of 88.9° and a phase transition temperature of 104.6-111.9 °C. Confocal laser scanning microscopy revealed Na+ mainly distributed at the oil-water interface of HIPEs through electrostatic load of CMS, accompanied by a few in water phase, while functional oil rich in unsaturated fatty acids was encapsulated in dispersion phase of HIPEs. This spatial distribution and ordered structure (fractal dimension is 1.54) of OCCNPs at the interface enhanced the thermal stability of HIPEs, helping to inhibit hazardous compounds and reduce salt addition. Evaluation of HIPEs-based biscuits demonstrated a remarkable reduction in lipid hydroperoxide (46.5 %), malondialdehyde (27.4 %), and 5-hydroxymethylfurfural (75.7 %). Additionally, OCCNPs-stabilized HIPEs improved saltiness perception, allowing for a 52 % reduction in salt content while achieving higher sensory scores. The thermostable and multifunctional HIPEs we have developed are conducive to the development of the food safety field.

Photo-activated Carbon dots (CDs) as Catalysts in the Knoevenagel Condensation: A Mechanistic Study by Dual-Mode Monitoring via ESI-MS

Carbon dots (CDs) obtained from 5-(hydroxymethyl)furfural (5-HMF) were activated by a 365 nm-UV irradiation source and employed in the Knoevenagel condensation to investigate their photocatalytic mechanism. To this end, electrospray ionization mass spectrometry (ESI-MS) was used to monitor the time progress of the condensation and follow the formation of the final product in positive and negative ion modes at once. The intervention of the superoxide radical anion in the photocatalytic mechanism of CDs was highlighted.

Green and Sustainable Forward Osmosis Process for the Concentration of Apple Juice Using Sodium Lactate as Draw Solution

China is the world's largest producer and exporter of concentrated apple juice (CAJ). However, traditional concentration methods such as vacuum evaporation (VE) and freeze concentration cause the loss of essential nutrients and heat-sensitive components with high energy consumption. A green and effective technique is thus desired for juice concentration to improve product quality and sustainability. In this study, a hybrid forward osmosis-membrane distillation (FO-MD) process was explored for the concentration of apple juice using sodium lactate (L-NaLa) as a renewable draw solute. As a result, commercial apple juice could be concentrated up to 65 °Brix by the FO process with an average flux of 2.5 L·m-2·h-1. Most of the nutritional and volatile compounds were well retained in this process, while a significant deterioration in product quality was observed in products obtained by VE concentration. It was also found that membrane fouling in the FO concentration process was reversible, and a periodical UP water flush could remove most of the contaminants on the membrane surface to achieve a flux restoration of more than 95%. In addition, the L-NaLa draw solution could be regenerated by a vacuum membrane distillation (VMD) process with an average flux of around 7.87 L∙m-2∙h-1 for multiple reuse, which further enhanced the long-term sustainability of the hybrid process.

Heterotrophic and autotrophic production of L-isoleucine and L-valine by engineered Cupriavidus necator H16

Advancement in commodity chemical production from carbon dioxide (CO2) offers a promising path towards sustainable development goal. Cupriavidus necator is an ideal host to convert CO2 into high-value chemicals, thereby achieving this target. Here, C. necator was engineered for heterotrophic and autotrophic production of L-isoleucine and L-valine. Citramalate synthase was introduced to simplify isoleucine synthesis pathway. Blocking poly-hydroxybutyrate biosynthesis resulted in significant accumulation of isoleucine and valine. Besides, strategies like key enzymes screening and overexpressing, reducing power balancing and feedback inhibition removing were applied in strain modification. Finally, the maximum isoleucine and valine titers of the best isoleucine-producing and valine-producing strains reached 857 and 972 mg/L, respectively, in fed-batch fermentation using glucose as substrate, and 105 and 319 mg/L, respectively, in autotrophic fermentation using CO2 as substrate. This study provides a feasible solution for developing C. necator as a microbial factory to produce amino acids from CO2.

Quality changes of HHP orange juice during storage: Metabolomic data integration analyses

High hydrostatic pressure (HHP) is a non-thermal method of sterilizing orange juice. However, knowledge of the quality variation during its storage is limited. This study aimed to comprehensively analyze metabolite variations during HHP orange juice storage using gas chromatography-mass spectrometer and liquid chromatography-mass spectrometry. Fifty-seven volatiles and 49 non-volatiles were identified. Partial least square analysis results showed that 21 days was a dividing point for metabolites highly varied. Results of relative odor activity value showed nonanal, methyl butanoate, and ethyl butanoate decreased after six days, which might reduce fruity flavor. After 21 days, over 60 % of metabolites such as linalool, α-pinene, and ascorbic acids decreased while α-terpineol and limonin increased, which would likely result in a change of coniferous, tarry, and bitter, as well as decreased organoleptic quality and antioxidative activities. This study provides a theoretical basis to optimize the shelf-life of HHP orange juice and advice for consumers' choices.

Exploring correlations between green coffee bean components and thermal contaminants in roasted coffee beans

This study evaluated chemical compositions of green coffee beans from multi-production regions and correlated this information with thermal contaminants in roasted coffee. Using multivariate statistical techniques, formation of 5-hydroxymethylfurfural (5-HMF), furan, 2- and 3-methylfuran were positively correlated with lipid, sucrose, glutamic acid, phenylalanine, margaric acid, linolenic acid and trigonelline in green coffee beans. Moreover, significant positive correlations between acrylamide (AA) levels with aspartic acid, serine, alanine, histidine, asparagine, protein, and caffeine was found in green beans. Despite this, 5-HMF, furan, 2- and 3-methylfuran showed negative correlations with active constitutes (neochlorogenic acid, cryptochlorogenic acid, caffeine, total phenolics (TPC) and total flavonoids contents (TFC)), and several amino acids, and there were slight negative relationships between AA and myristic acid, palmitic acid, chlorogenic acid, sucrose, lipid, TPC and TFC. This study provides valuable enlightenment for the selection of proper coffee beans for production of coffee with high nutrition and low chemical hazardous risks.

Formation of Amadori compounds in LIGAO (concentrated pear juice) processing and the effects of Fru-Asp on cough relief and lung moisturization in mice

LIGAO (concentrated pear juice) has been used for more than 1000 years to treat respiratory complaints such as cough and expectoration in China, but the study of the mechanism of its antitussive effects and ability to moisten the lungs is limited. This study found that the content of Amadori compounds (ACs) and other nutrients changed during LIGAO processing. Furthermore, N-(1-deoxy-D-fructos-1-yl)-aspartic acid (Fru-Asp), the most abundant and characteristic AC in LIGAO, was prepared and studied. The antitussive test revealed that Fru-Asp could significantly reduce the frequency of cough and prolong the cough latent period in mice. A high dose of Fru-Asp (250 mg kg^-1) in mice provided better therapeutic activities than that of dextromethorphan hydrobromide tablets (30 mg kg^-1). In the Fru-Asp pretreated group, Fru-Asp significantly alleviated inflammation in LPS-induced acute lung injury mice. Fru-Asp can significantly decrease the levels of TNF-α and IL-β in mice by 11%. Additionally, Fru-Asp exhibited angiotensin-converting enzyme (ACE) inhibitor activity (IC₅₀ = 0.242 mM). The contribution and health benefits of Fru-Asp on cough relief were first reported in this study, which also substantiated it as a functional component of LIGAO. The results provided the basis for future research on the health effects of ACs and a method to improve the added value of LIGAO and other pear products.

Supercritical CO2 Processing of a Functional Beverage Containing Apple Juice and Aqueous Extract of Pfaffia glomerata Roots: Fructooligosaccharides Chemical Stability after Non-Thermal and Thermal Treatments

The effects of supercritical CO₂ processing on the chemical stability of fructooligosaccharides (FOS) and other functional and nutritional compounds were evaluated employing non-thermal and thermal approaches. Apple juice was enriched with Pfaffia glomerata roots aqueous extract due to its high content of short-chain FOS and then subjected to different levels of temperature (40 and 60 °C), pressure (8 and 21 MPa), and CO₂ volume ratio (20 and 50%). The percentage of CO₂ volume was evaluated concerning the total volume of the high-pressure reactor. Also, the functional beverage was thermally treated at 105 °C for 10 min. Physicochemical properties (pH and soluble solid content), beta-ecdysone, sugars (glucose, fructose, and sucrose), and FOS (1-kestose, nystose, and fructofuranosylnystose) content were determined. The pH and soluble solid content did not modify after all treatments. The pressure and CO₂ volume ratio did not influence the FOS content and their chemical profile, however, the temperature increase from 40 to 60 °C increased the nystose and fructofuranosylnystose content. High-temperature thermal processing favored the hydrolysis of 1-kestose and reduced the sucrose content. Regarding beta-ecdysone, its content remained constant after all stabilization treatments demonstrating thus its high chemical stability. Our results demonstrated that supercritical CO₂ technology is a promising technique for the stabilization of FOS-rich beverages since the molecular structures of these fructans were preserved, thus maintaining their prebiotic functionality.