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Copyright of China Condiment is the property of China Condiment and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Orange juice is highly popular among consumers for its unique taste, flavor, and nutritional value. However, orange juice is susceptible to browning, resulting in loss of quality. The browning of orange juice is complex, especially non-enzymatic browning (NEB), and its main mechanism has not been reported. In this study, the browning of concentrated orange juice (COJ) was determined to be NEB during storage by detecting polyphenol oxidase and peroxidase activities. A simulation system based on the main components of COJ was established to explore the main mechanisms of NEB. The browning products (5-HMF, A294) and browning indexes (BI values, ΔE) of the simulation system showed that the contribution of the Maillard reaction (0.085) to browning was slightly greater than ascorbic acid degradation (0.078) and 28 times greater than caramelization reaction (0.003). This suggests that ascorbic acid degradation and the Maillard reaction are the main factors to NEB of COJ, while the caramelization reaction and phenolic oxidation can be ignored. Moreover, the browning in the early stage of storage was mainly caused by the degradation of ascorbic acid, and the later stage was Maillard reaction. In summary, the browning of COJ during storage is mainly caused by ascorbic acid degradation and Maillard reaction with different stages of action. Developing browning inhibition strategies for COJ should focus on the main browning factors at different stages to regulate browning more precisely and protect the quality. [ABSTRACT FROM AUTHOR]

Summary: The global demand for dehydrated onion is on the rise, driven by the increasing consumer preference for ready‐to‐eat convenience foods. This study focused on enhancing the quality and functional properties of dehydrated onion slices (cv. Pusa Shobha) through different pre‐treatment and drying conditions. Fresh onion slices were subjected to pre‐treatment using NaCl (3%, 5% and 7%) and KMS (0.3%, 0.5% and 0.7%) solutions for 10 min, followed by tray drying at 50 °C, 60 °C and 70 °C temperatures for varying durations of 14, 12 and 10 h, respectively. Based on physicochemical and functional properties, onion slices pretreated with 5% NaCl + 0.5% KMS and dehydrated at 60 °C for 12 h retained higher bioactive compounds like total phenols (166.32 mg GAE 100 g−1 DW), total flavonoids (28.94 mg QE g−1 DW), ascorbic acid (12.45 mg 100 g−1 DW), quercetin (172.88 μg g−1 DW) and total antioxidant activity (24.59 μmol TE g−1 DW). Additionally, it maintained superior sensory acceptability with higher pungency (7.15 μmol g−1 DW), dehydration ratio (9.25%), rehydration ratio (5.20%), lower non‐enzymatic browning (0.36) and moisture content (5.75%). Hence, the optimised treatment of 'Pusa Shobha' slices with 5% NaCl + 0.5% KMS, followed by dehydration at 60 °C for 12 h, yields dehydrated onion slices with superior bioactive compounds, sensory acceptability, and enhanced functional properties. The findings of his research offer valuable technology for the food industry, providing a practical and efficient method to produce high‐quality dehydrated onion slices. [ABSTRACT FROM AUTHOR]

Orange juice shows browning issue during storage which seriously affects its quality. Based on our previous study demonstrating the inhibition of browning of concentrated orange juice (COJ) by epigallocatechin gallate (EGCG) and L-cysteine (L-cys), this study evaluated the effect of ultrasonic-vacuum combined with high-pressure CO2 on browning. Ultrasonic-vacuum can reduce the dissolved oxygen content in COJ more effectively than ultrasonic and also minimize the loss of ascorbic acid. The lowest dissolved oxygen content and ascorbic acid loss in COJ were achieved by ultrasonic-vacuum at 900 W and 15.6 min for COJ sample of 50.0 g. Ultrasonic-vacuum effectively removes most of the dissolved oxygen from COJ, and high-pressure CO2 reduces oxygen in the headspace of the container. This reduction in oxygen content effectively reduces aerobic acid degradation and inhibits browning caused by ascorbic acid degradation. In addition, the results showed that although ultrasonic-vacuum combined with high-pressure CO2 had a significant effect on delaying ascorbic acid degradation and reduced the loss by 35.01%, it has little effect on browning caused by Maillard reaction. Finally, it is concluded that ultrasonic-vacuum combined with high-pressure CO2 based on EGCG and L-cys has the best inhibitory effect on browning of COJ during storage, inhibiting 69.8% of the increase in BI values. [ABSTRACT FROM AUTHOR]

ABSTRACTTo investigate the effect of adding high-dose docosahexaenoic acid (DHA) and arachidonic acid (ARA) on the stability of infant formula powders (IFs), IFs fortified with high-dose and low-dose DHA and ARA were compared and evaluated during storage at 37°C for six months. We specifically focused on the changes to IFs caking, amino acid content, and 5-hydroxymethylfurfural (HMF) content. We found that during the storage process, there was no significant change in the amino acids of IFs following supplementation with high- or low-doses of DHA and ARA. However, HMF and color difference (∆E) increased with the length of storage time. A comparison between the high-dose and low-dose groups revealed that the addition of high-dose DHA and ARA did not cause an additional increase in the HMF but exacerbated the caking of IFs. The addition of high-dose DHA and ARA did not exacerbate the non-enzymatic browning of IFs.

The enzymatic browning of fresh-cut lotus rhizomes has been studied extensively at present, but few people pay attention to the quality deterioration of whole lotus rhizomes caused by non-enzymatic browning. In this study, we first screened the compound inhibitors for the blackening of lotus rhizome by color difference and sensory properties and then investigated the effects of blackening compound inhibitors on storage quality and shelf life of lotus rhizome. Results showed that the combination of 0.9% sodium alginate, 2% EDTA-2Na, 5% glycerol and 0.5% potassium sorbate (ENCI-4) had the best color difference and sensory properties of the lotus rhizome. Moreover, after 60 d of low-temperature storage, it was found that the sensory scores, SSC and total phenols contents of the lotus rhizomes treated with ENCI-4 were significantly higher than those in control groups (p < 0.05), while the color difference, total acid, MDA contents, total bacterial, mold and yeast count were significantly lower than those in control groups (p < 0.05). Besides, by comparing the storage quality of bruised lotus rhizomes (CK-1) and mud-treated lotus rhizomes (CK-2), it was found that the formation of epidermal blackening in CK-2 would accelerate the browning and aging rates of lotus rhizomes, thereby having a more negative impact on its storage quality, while the shelf life of lotus rhizome could be significantly extended after ENCI-4 treatment. Overall, the blackening compound inhibitor formula proposed in this study can effectively extend the shelf life of the whole lotus rhizome. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a study on kinetic and thermodynamic compensation to evaluate the kinetics of non-enzymatic browning of clarified lemon juices. In a previous work, the kinetic constants of browning were presented using the evolution of the absorbance at 420 nm (A420) and luminosity (L*) for different soluble solids contents (64.6; 50; 35; 20 and 10 ºBrix) and different working temperatures (70, 80, 90 and 95 ºC). The parameters of the Arrhenius equation were obtained by fitting the kinetic constants and temperatures. The variation of lnK0 with Ea follows a linear trend, so there is kinetic compensation, with isokinetic temperature values being 126.6 ºC and 149.7 ºC for A420 and L*, respectively. The transition state equilibrium constants were determined using the Eyring equation for each soluble solids content and each temperature. The equilibrium constants were adjusted to the Van't Hoff equation and the set of pairs of estimated values for the activation enthalpy and the activation entropy also followed a straight line, which causes thermodynamic compensation, with isoequilibrium temperatures of 112.8 ºC and 136.3 ºC for A420 and L*, respectively. It was concluded that the browning mechanism is the same for the ranges of soluble solids content and temperature studied. Since all isokinetic and isoequilibrium temperatures were higher than the working temperature values, it was also concluded that the control was enthalpic for all cases. To avoid the deterioration of these juices, it is advisable to intervene in the working temperature, trying to ensure that the heat treatment is carried out at the lowest possible temperature. [ABSTRACT FROM AUTHOR]

Objective: Indigo fruit juice is prone to browning during processing. Methods: A kinetic model was fitted by determining the changes in browning degree, vitamin C （VC） content, and 5-hydroxymethylfurfural （5-HMF） content of indigo fruit juice during the sterilization process. Results: The optimal conditions were obtained by single factor and response surface optimization test, and the changes of microbiological, physicochemical and sensory indexes of the optimized indigo juice were measured during storage at 4, 25 and 37 ℃ for 30 days. The results showed that the changes in Browning degree, VC and 5-HMF content were consistent with the joint, first-order and zero-order reaction kinetics models, respectively. The optimal conditions of single factor and response surface optimization were as follows: dosage 0.21%, temperature 39 ℃, time 45 min, and inhibition rate of non-enzymatic Browning was 95.13% under these conditions. At 4 ℃, the juice test indexes of indigo juice changed relatively slowly. At the end of storage, the total number of colonies was less than 100 CFU/mL, and the contents of soluble solids, total phenols, anthocyanins, VC and reducing sugars were relatively high. They were 14.15%, 262.02 g/100 g, 380.50 mg/L, 65.37 mg/L and 9.62 g/100 g, respectively, with sensory scores of 82.3 points, with the fruit aroma and fruit taste, uniform color and uniform texture of indigo fruit. Conclusion: Through experiments, the browning of indigo juice during storage was significantly inhibited.

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fruit juices are a rich source of the bioactive compounds. Most fruit juices are rich in vitamins and organic acids that are easily absorbed by the human body. However, improper processing methods will weaily lead to stored juice suffers adverse browning reactions, which has been an important problem faced by the juice processing industry. Increasing consumer demand for safer, more nutritious products has made it difficult for traditional browning control technologies to meet the need of consumers, this has contributed to the rapid development of non-traditional processing technologies. In this paper, the traditional browning prevention and control methods are briefly summarized, and several emerging non-thermal processing techniques are detailed reviewed along with an assessment of their commercialization potential and their application advantages. [ABSTRACT FROM AUTHOR]

The Maillard reaction is well known for producing antioxidant compounds alongside colored substances. Low-molecular-weight antioxidant intermediates such as maltol (MAL) or norfuraneol (NF) are well described, but it is still unclear which of these Maillard intermediates are the precursors of antioxidant and colored melanoidins—the so-called late stage Maillard reaction products. This study aimed to provide novel insights into the correlation between browning potential and antioxidant properties of reaction products formed during the heat treatment of prominent Maillard reaction intermediates. It was achieved by the incubation of binary reaction systems composed of methylglyoxal (MGO) or NF in combination with furfural (FF), MAL, and pyrrole-2-carbaldehyde (PA) at pH 5 and 130 °C for up to 120 min. Overall, it could be shown that the formation of colored products in the binary NF reaction systems was more efficient compared to those of MGO. This was reflected in an increased browning intensity of up to 400% and a lower conversion rate of NF compared to MGO. The colorants formed by NF and FF or PA (~0.34 kDa and 10–100 kDa) were also found to exhibit higher molecular weights compared to the analogue products formed in the MGO incubations (<0.34 kDa and 10–100 kDa). The incorporation of NF into these heterogenous products with FF and PA resulted in the preservation of the initial antioxidant properties of NF (p < 0.05), whereas no antioxidant products were formed after the incubation of MGO. [ABSTRACT FROM AUTHOR]

Choerospondias axillaris, snow pear, and apple composite fruit puree can be affected by non-enzymatic browning during storage decreasing the market value of the product. This study aimed to explore, using kinetic methods, the effects of non-enzymatic precursors (polyphenols and ascorbic acid) and intermediates (5-hydroxymethylfurfural) on fruit puree stored at 4 °C for 35 days. The results showed that ascorbic acid fitted the first-order reaction model, while the 5-hydroxymethylfurfural was consistent with the complex reaction model. Furthermore, the 5-hydroxymethylfurfural content was 1.53 ± 0.18 mg/L, (corresponding to an increase of 565%), and the ascorbic acid content was 0.88 ± 0.22 mg/100 g, (corresponding to a decrease of 98.5%). The results also demonstrated a change in the titratable acid, soluble solids, and pH of the fruit puree. Finally, the correlation results revealed a significant correlation between non-enzymatic browning and 5-hydroxymethylfurfural, titratable acid, and pH (p < 0.05). Overall, the results suggest that the Maillard reaction could be responsible for the non-enzymatic browning of fruit purees during storage. [ABSTRACT FROM AUTHOR]

Chinese yam is a kind of food with high nutritional value. Browning is one of the main problems affecting the quality of Chinese yam during processing and storage. It is of great significance to effectively control the browning of Chinese yam, maintain its color and nutritional characteristics, and improve its shelf life in order to guarantee the quality of Chinese yam and improve the acceptance of consumers. On the basis of previous studies, the mechanism of enzymatic browning and non-enzymatic browning of Chinese yam are described in this paper. The mechanism of enzymatic browning of Chinese yam is explained by three elements of enzymatic browning including phenolic substrate, enzyme and oxygen, and the mechanism of Maillard reaction and non-enzymatic browning of caramelization in processing and storage of Chinese yam are introduced. In this paper, the control effects of different browning control techniques on Chinese yam are summarized, the existing problems are analyzed, and the future prospects are prospected, in order to provide reference for the research and application development of control techniques on Chinese yam browning.

Green rooibos' bioactive compounds contribute greatly towards its antioxidant activity. The anti-browning activity of aqueous (GRE) and beta-cyclodextrin (β-GRE)-assisted extracts of green rooibos was investigated in canned apples. Freeze-dried extracts (GRE and β-GRE) obtained at 40 °C for 60 min were added in canned apples at 0.25 and 0.5% prior to heat processing and stored at 23 and 37 °C for 24 weeks. Lightness (L*), colour difference (DE*), furfural and hydroxymethyl furfural (HMF) were determined to establish the effect of extracts against non-enzymatic browning (NEB) development. The L* value decreased, whereas DE*, HMF and furfural increased with increased storage time and temperature. A higher inhibition was observed for samples stored at 23 °C, and storage at 37 °C reduced (p < 0.05) the inhibitory capacity of extracts. Greater inhibition against NEB development was reported for β-GRE 0.25 and 0.5 via the L* value (40.93–46.67%), β-GRE 0.25 for DE* (46.67%) and β-GRE 0.25 and 0.5 for HMF (59.55–67.33%). No differences (p > 0.05) were observed in furfural inhibition between all extracts, although inhibition was reported at 62.69–72.29%. Browning inhibition correlated with the reaction rate constant (k0) and activation energy (Ea), exhibiting a correlation coefficient of 0.925, 0.964, 0.932 and 0.754 for L*, DE*, HMF and furfural, respectively. [ABSTRACT FROM AUTHOR]

In order to study the changes of main substances causing non-enzymatic browning of sea buckthorn wine during storage at room temperature and their relations with browning, these indexes of the browning degree, total phenol, 5-hydroxymethyl furfural (5-HMF), ascorbic acid (VC), reducing sugar, total acid and dissolved oxygen were determined during storage. The main factors influencing non-enzymatic browning of sea buckthorn wine during storage were analyzed by correlation analysis and path analysis. The results showed that the browning degree of sea buckthorn wine increased with the storage time at 25 ℃. The contents of total phenol and VC decreased gradually and the content of 5-HMF increased gradually. The total acid content decreased gradually, and the content of reducing sugar and dissolved oxygen decreased first and then increased. Among them, 5-HMF had the strongest direct effect on sea buckthorn wine browning degree. The interaction between 5-HMF and total phenols was the first determinant of the non-enzymatic browning degree of sea buckthorn wine, which were the main causes of non-enzymatic browning during the room temperature storage of sea buckthorn wine.

[Display omitted] • Epigallocatechin and epicatechin are favorable for red pigments formation. • Organic acids are unfavorable to the formation of red pigments. • Reducing pH, dephenolization and chelating agents are not conducive to red pigments. • The formation of red pigment in red sup belongs to non-enzymatic Browning reaction. • The chelation of iron-polyphenols may be unfavorable to the formation of red pigment. Lotus rhizome soup, renowned as a unique delicacy made from lotus rhizome, is cherished by many consumers. However, the varying colors of soup are sure to influence individuals' appetites. This research focused on the Miancheng lotus Rhizome (MLR) and Elian No. 6 lotus rhizome (ELR) to investigate the relationship between the variations in polyphenols, organic acids and iron levels in MLR and ELR soups during the cooking process. The findings indicated that cooking MLR for 12 min resulted in a red soup with a * value of 8.65 ± 0.12, whereas the soup made from ELR remained white with a * value of 3.43 ± 0.08. The correlation analysis results indicated that polyphenols, specifically epigallocatechin (0.0169 ± 0.00029 μg/100 mL FW after cooking for 12 min) and epicatechin (0.0211 ± 0.00047 μg/100 mL FW after cooking for 12 min), exhibited a significant positive relationship with a * (p < 0.05). Moreover, lowering the pH, removing polyphenols and incorporating metal-chelating agents can also prevent the development of red pigment. The analysis from HPLC-MS, UV–Vis, FT-IR spectra and ESI-Q-TOF-MS indicated that the development of the red soup color involved i) the generation of epicatechin gallate through the enantiomeric reaction of epigallocatechin, ii) the co-chromic red interaction between anthocyanin cations and catechol structures, and iii) the formation of polyphenol oligomers (i.e. , procyanidin A2, (+)-procyanidin B2, procyanidin C1 and prodelphinidin B4) due to heating, while the creation of phenol-iron chelates could inhibit the development of red coloration. In sum, this research introduces a new idea for managing the color of lotus rhizome soup and similar soup products. [ABSTRACT FROM AUTHOR]

Black garlic (BG) is an aged product high in brown melanoidin pigment and functional quality, however, the long aging process limits its commercial production. The present investigation was undertaken to develop an innovative process for improving the functional quality of BG as well as shortening the aging duration. Peeled garlic was subjected to two pre-treatment steps viz. Freeze-thaw (FT) and blanching (BL) followed by ascorbic acid (AA) infusion and effects were monitored during aging. Non-enzymatic browning, the main visible indicator of MR was significantly (p < 0.05) high in FT garlic due to high infused AA content. The pre-treated garlic showed significantly (p < 0.05) high fructose content (6-7-fold) over the control on the 6th day of aging. The treatment also enhanced the total phenolic content (2.5–3.0-fold) and antioxidant activity (14-fold) while reducing the processing time from 18 to 12 days. The soluble solid content (58.7 °B) and Fast index (fluorescent of advanced Maillard reaction products and soluble tryptophan) was maximum (305.2) in FT garlic on the 12th day. FTIR confirmed a strong peak at 1515 cm−1 depicting the dark nature of the BG subjected to FT. The innovative short process saved 50% of energy in production and was 43% more economical compared to its control counterpart. Overall sensory quality of FT garlic in terms of color, flavour and texture was on par with control except BL sample which showed high stickiness and low score values. Overall results suggest that FT treatment followed by infusion of ascorbic acid accelerated the Maillard reaction (MR), and improved the functional quality of BG. [Display omitted] • Effect of freeze-thaw and ascorbic acid infusion on black garlic. • The pre-treatments accelerated aging and Maillard reaction. • The process time was reduced from 18 to 12 days. • Innovative short process for developing black garlic is proposed. [ABSTRACT FROM AUTHOR]

The unknown effect of sesame lignans on aroma formation in sesame oil via the Maillard reaction (MR) and lipid oxidation was investigated. Sesamin, sesamolin, or sesamol was added to 3 models: lysine+glucose (MR), cold-pressed sesame oil (SO), and MR + SO, and were heated at 120 °C for 60 min. All three lignans suppressed SO oxidation while increasing DPPH scavenging ability (p < 0.05). Lignans increased depletions of lysine and glucose and MR browning (p < 0.05). Lignans reduced most aroma-active pyrazines, aldehydes, ketones, alcohols, and esters (p < 0.05). Sesamol and sesamolin increased perceptions of the preferable aromas of nutty, roasted sesame, and popcorn while reducing the undesirable green and rancid aromas (p < 0.05). Sesamol demonstrated a stronger effect on lipid oxidation, MR browning, aroma formation, and sensory perception than sesamin and sesamolin. This study suggests that sesame lignans can modulate aroma formation and sensory perception of sesame oil by interacting with the MR and lipid oxidation pathways. [Display omitted] • Sesame lignans affected aroma formation of sesame oil via the MR & lipid oxidation. • Sesamin, sesamolin & sesamol reduced AV, POV, p -AnV, and increased OIT of sesame oil. • Sesamin, sesamolin & sesamol increased lysine & glucose depletion and MR browning. • Sesamin, sesamolin & sesamol reduced the formation of most pyrazines and aldehydes. • Sesamolin & sesamol improved nutty & popcorn aromas, reduced green & rancid aromas. [ABSTRACT FROM AUTHOR]

Hot air drying (HAD) is an extensive method used on oysters and it causes the most intuitive change, a color change. However, the mechanism of color change remains unclear. This study showed that oysters underwent browning during the HAD process. The colorimetric parameter L * decreased while a * and b * increased, all of which were well described by the first-order color kinetic model. Mechanistically, the HDA process induced the oxidative browning of phenols and the generation of Maillard reaction products (5-hydroxymethylfurfural and hydrophilic pyrrole). Meanwhile, the HAD process caused lipid oxidation, leading to the reduction of phosphatidylethanolamine and the generation of reactive carbonyl compounds (aldehydes and α-dicarbonyl compounds). Moreover, the accumulation of hydrophobic pyrroles, a lipid-induced Maillard-like reaction product, was observed. These results suggest that, in addition to phenolic oxidation, sugar- and amino acid-mediated non-enzymatic browning reactions, lipid-mediated Maillard-like reactions play important roles in oyster darkening during the HAD process. • Effects of non-enzymatic browning on oysters during HAD process are investigated • Changes in L *, a *, b * of oysters during the HAD process are consistent with first-order kinetic models • Lipid-mediated Maillard-like reaction plays a crucial role in color change of oysters • Maillard reaction, phenolic oxidation, and lipid-related NEBRs work together to darken oysters [ABSTRACT FROM AUTHOR]

As a traditional fermentation food, red sour soup (RSS) is very popular in China. However, browning is always occurred during the process of fermentation, which influences the sensory quality of RSS and limits its further application. Thus, it is meaningful to elucidate the main factors related to browning during the process of fermentation. Herein, the changes in various factors related to browning from group spontaneous (RSS-SF) and inoculant fermentation (RSS-IF) were determined and analyzed. Firstly, the activity changes of enzymes related to browning indicated that browning of group RSS-SF and RSS-IF during fermentation was not related to enzymatic browning. Secondly, path analysis revealed that the main factors related to non-enzymatic browning of group RSS-SF and RSS-IF were oxidation of polyphenol and degradation of ascorbic acid (Vc). The results of this study not only identifies the main factors associate with browning of RSS, but also provides foundation on how to control the browning of RSS in further study.

The browning of plant-based food is commonly understood to result from the enzymatic polymerization of phenolic compounds to pigments, called melanin. However, during the thermal treatment of food, enzymes are deactivated, and non-enzymatic reactions predominate. The extent of the contribution of phenolic compounds to these non-enzymatic reactions has been speculated ("melanin-like vs. melanoidin-like"), but the literature is limited. Therefore, the aim of the present study was to investigate the heat-induced reactions of caffeic acid (CA), para-coumaric acid (CS), ferulic acid (FA), hydrocaffeic acid (HC), and 5-O-caffeoylquinic acid (CGA) under dry conditions. The model systems were characterized by color formation, reactant conversion, and antioxidant properties. Reaction products were analyzed by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy. Decarboxylation could be classified as the driving force for the observed color formation and was significantly impacted by the substitution of the aromatic system. Reaction products were found to contribute to an increase in the antioxidant properties of the model systems. The oligomers described in this study could be incorporated into food melanoidins, contributing to the color and antioxidant properties observed in roasted food rich in phenolic compounds, such as coffee or cocoa. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The non-enzymatic browning of glucosamine (GlcN) under UV-C radiation at 25°C, referred to as “cold caramelization”, was examined. Several UV-C exposure times of 0, 20, 60, 120 min at two GlcN concentrations of 15% and 30% were chosen. The physicochemical properties, quantitation of α-dicarbonyl compounds and polyhydroxyalkyl pyrazines, alkylimidazoles and 5-hydroxymethylfurfural were determined in UV-C exposed GlcN caramels. The results revealed the possibility of generating GlcN caramel containing desirable compounds by applying UV-C. Longer UV-C exposure time produced caramel with higher content of glucosone and 3-deoxyglucosone, as well as the GlcN self-condensation products, fructosazine and deoxyfructosazine. Importantly, none of the tested neo-formed contaminants were detected in resulted caramels. Thus, UV-C treatment may be a newly advantageous method for producing GlcN caramel.

The Maillard reaction is well known for producing antioxidant compounds alongside colored substances. Low-molecular-weight antioxidant intermediates such as maltol (MAL) or norfuraneol (NF) are well described, but it is still unclear which of these Maillard intermediates are the precursors of antioxidant and colored melanoidins—the so-called late stage Maillard reaction products. This study aimed to provide novel insights into the correlation between browning potential and antioxidant properties of reaction products formed during the heat treatment of prominent Maillard reaction intermediates. It was achieved by the incubation of binary reaction systems composed of methylglyoxal (MGO) or NF in combination with furfural (FF), MAL, and pyrrole-2-carbaldehyde (PA) at pH 5 and 130 °C for up to 120 min. Overall, it could be shown that the formation of colored products in the binary NF reaction systems was more efficient compared to those of MGO. This was reflected in an increased browning intensity of up to 400% and a lower conversion rate of NF compared to MGO. The colorants formed by NF and FF or PA (~0.34 kDa and 10–100 kDa) were also found to exhibit higher molecular weights compared to the analogue products formed in the MGO incubations (p < 0.05), whereas no antioxidant products were formed after the incubation of MGO.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To produce cooked rice that can be stored under a chilled condition, the effect of maltotriose syrup on the retrogradation of gelatinized rice starch and cooked rice was investigated using dynamic mechanical thermal analysis, rheometer, differential scanning calorimetry, and sensory analysis. The storage modulus (G') of gelatinized rice starch increased considerably after chilled storage at 5 °C for up to 72 h. The time course of the G' corresponded to that of the re-gelatinization enthalpy of retrograded starch. The G' decreased with increasing maltotriose syrup content, but there was no significant difference in the G' between samples with 20% and 30% maltotriose syrup. According to the results, cooked rice samples with (additive samples) and without (non-additive samples) 20% maltotriose syrup were prepared with preset water contents of 60% and 65%. After chilled storage at 5 °C for 24 h, the G' and hardness (force generated by 50% compressive strain) of the additive samples were much lower than those of the non-additive samples. In addition, the G' and hardness decreased with increasing water content. The G' of the additive sample with a preset water content of 65% was lower than that (G' = 26.9 kPa) of the tolerance limit determined by the sensory analysis. However, the additive samples showed substantial browning. The pH of the samples was adjusted to diminish the browning. The color parameter (b*) did not differ significantly between the additive sample at pH 5.5 and the non-additive sample at pH 7.0. [ABSTRACT FROM AUTHOR]

[Display omitted] • The blue change of boiled lotus rhizome discs (BLRDs) was non-enzymatic browning. • The blue pigment may be mainly due to the complexation of iron and polyphenols. • The main polyphenols that caused bluing of BLRDs were L-dopa and gallocatechin. • L-dopa-iron and catechin-iron were chelated in form of bis-complexes in this study. Boiled lotus rhizome discs (BLRDs), as common processed products of lotus rhizome, have gained increasing attention from consumers and food manufacturers. However, the blue pigment formed during boiling affects its appearance and reduces the appetite of BLRDs. In this study, the effects of polyphenols and iron contents on blue pigment formation in BLRDs in different regions and months were investigated. Results revealed that blue variation was more serious in March and April of the second year in Wuhan, and polyphenols and iron contents in these two months were significantly higher than those in other months. Then, UPLC and UV–Vis analysis showed that polyphenols causing the formation of blue pigment in BLRDs were L -dopa, gallocatechin, catechin, epigallocatechin, chlorogenic acid and epicatechin, among which L-dopa (52.450 mg/100 g in fresh lotus rhizome (FLR)) and gallocatechin (36.210 mg/100 g in FLR) possessed the greatest effect. Moreover, the ESI-Q-TOF-MS analysis of L -dopa-iron chelate and gallocatechin-iron chelate suggested that the blue pigment of BLRDs was mainly in the form of bis-complexes under boiling conditions. The study on formation mechanism of blue pigment in BLRDs can provide a reference for lotus rhizome processing. [ABSTRACT FROM AUTHOR]

Restructured foods are a blend of various ingredients that are dried or fried to obtain a ready-to-eat product. Several frying techniques have been employed viz., deep fat, microwave, vacuum, air, and spray frying. Deep-fat frying is the most common technique used for products that have improved texture and sensory characteristics. It facilitates various transformations that include starch gelatinization, protein denaturation, nutrient loss, non-enzymatic browning, lipid oxidation, etc. This physicochemical change alters both the product and the fried oil quality. The frying conditions will also influence the product characteristics and affect the properties of the fried product. This review focuses on the mechanisms and transformations during deep fat frying. The properties, namely physical, chemical, sensory, thermal, rheological, and microstructural changes of restructured foods were discussed. Thus, a better understanding of mechanisms and properties at optimum frying conditions would yield the desired product quality. • Restructured foods are a blend of ingredients that may be molded into desired shapes. • Bubble end point indicates frying completion by decreasing moisture loss. • Deep-frying develops a porous structure and crust formation after frying. • Optimizing deep-fat frying parameters can enhance restructured food characteristics. [ABSTRACT FROM AUTHOR]

The present research aimed to evaluate the effect of microwave-assisted conventional drying (hybrid drying) on the physico-chemical and functional characteristics of formulated instant banana-milk powders (IBSPs), and organoleptic attributes of banana-milk shakes during storage. The instant powders were prepared from ripe (IBSP1 (control) and IBSP2) and overripe (IBSP3) bananas using hot-air drying (control) and hybrid (microwave assisted hot-air) drying. The water holding capacity, water solubility index, and viscosity of fresh samples, IBSP1, IBSP2, and IBSP3 were 1.97, 1.53 and 0.60 g/g dry sample, 69.48, 75.21 and 76.62 g/mL and 82.29, 86.29 and 72.55 mPas, respectively. A significant (p < 0.05) increase in moisture content, water activity (aw), acidity, and non-enzymatic browning was observed in all the variants/samples during storage. Among various treatments, the shakes prepared by reconstitution (IBSP: water ratio, 1:4) of IBSP2 formulation rated highest organoleptically (significant, p < 0.05). [ABSTRACT FROM AUTHOR]

Nectarine fruit is highly perishable due to its high moisture content (89%) and susceptibility to decay. Continuous degradation in quality attributes due to physiological responses and ripening result ultimately in post-harvest losses. Drying of fruit offers the possibility to minimize losses and add value to fresh produce. Thus, this study evaluated the impacts of sodium metabisulphite (SMB; 10 g/kg) and characterized the influence of hot air (50 °C) drying on the kinetics, fruit tissue microstructure, and the physicochemical properties of dried 'Sunectwentyone' nectarines (Super star®). Out of the nine mathematical models, Logarithmic and Henderson, and Pabis models were the most suitable to predict the drying behaviour of sliced nectarines (R2 = 0.94). Based on the microstructural analysis, prolonged drying led to higher tissue displacement/disruption in dehydrated nectarine slices. Results showed that SMB treatment was more effective in maintaining both the freshness and the color of 'Sunectwentyone' nectarine than the untreated. [ABSTRACT FROM AUTHOR]

Green rooibos’ bioactive compounds contribute greatly towards its antioxidant activity. The anti-browning activity of aqueous (GRE) and beta-cyclodextrin (β-GRE)-assisted extracts of green rooibos was investigated in canned apples. Freeze-dried extracts (GRE and β-GRE) obtained at 40 °C for 60 min were added in canned apples at 0.25 and 0.5% prior to heat processing and stored at 23 and 37 °C for 24 weeks. Lightness (L*), colour difference (DE*), furfural and hydroxymethyl furfural (HMF) were determined to establish the effect of extracts against non-enzymatic browning (NEB) development. The L* value decreased, whereas DE*, HMF and furfural increased with increased storage time and temperature. A higher inhibition was observed for samples stored at 23 °C, and storage at 37 °C reduced (p < 0.05) the inhibitory capacity of extracts. Greater inhibition against NEB development was reported for β-GRE 0.25 and 0.5 via the L* value (40.93–46.67%), β-GRE 0.25 for DE* (46.67%) and β-GRE 0.25 and 0.5 for HMF (59.55–67.33%). No differences (p > 0.05) were observed in furfural inhibition between all extracts, although inhibition was reported at 62.69–72.29%. Browning inhibition correlated with the reaction rate constant (k0) and activation energy (Ea), exhibiting a correlation coefficient of 0.925, 0.964, 0.932 and 0.754 for L*, DE*, HMF and furfural, respectively.

The browning of plant-based food is commonly understood to result from the enzymatic polymerization of phenolic compounds to pigments, called melanin. However, during the thermal treatment of food, enzymes are deactivated, and non-enzymatic reactions predominate. The extent of the contribution of phenolic compounds to these non-enzymatic reactions has been speculated (“melanin-like vs. melanoidin-like”), but the literature is limited. Therefore, the aim of the present study was to investigate the heat-induced reactions of caffeic acid (CA), para-coumaric acid (CS), ferulic acid (FA), hydrocaffeic acid (HC), and 5-O-caffeoylquinic acid (CGA) under dry conditions. The model systems were characterized by color formation, reactant conversion, and antioxidant properties. Reaction products were analyzed by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy. Decarboxylation could be classified as the driving force for the observed color formation and was significantly impacted by the substitution of the aromatic system. Reaction products were found to contribute to an increase in the antioxidant properties of the model systems. The oligomers described in this study could be incorporated into food melanoidins, contributing to the color and antioxidant properties observed in roasted food rich in phenolic compounds, such as coffee or cocoa.

BACKGROUND: Terminalia ferdinandiana, common name Kakadu plum (KP), fruit is a valuable source of vitamin C, and its concentration can be used as a quality index of KP products, such as dried fruit powder. The present study investigated the effects of two drying methods (freeze‐drying and oven‐drying) and the addition of maltodextrin (0–25%) on vitamin C, Maillard products, and overall quality of KP fruit powder. RESULTS: Freeze‐drying was a better dehydration technique than oven‐drying in retaining vitamin C, reducing the formation of non‐enzymatic browning and oxidation products, and improving powder colour (P < 0.05). Non‐enzymatic browning products (furfural and 5‐hydroxymethyl furfural) were generated in the oven‐dried samples as a function of heating and high water activity. Maltodextrin acted as a vitamin C stabilizer in protecting vitamin C from oxidation, and significantly improved the colour attributes of the final dry products. Incorporation of 10–15% maltodextrin could reduce the percentage loss of vitamin C from 8.1% to 3.4% and 18.9% to 11.4% (compared with the control) during freeze‐drying and oven‐drying, respectively. Scanning electron micrographs revealed differences in the microstructures of the KP powder processed by the two drying methods with different levels of maltodextrin. Multivariate data analysis (principal component analysis) showed separation between the oven‐dried and freeze‐dried samples, and also suggested that addition of maltodextrin of 7.5–10% and 10–15% are effective for preserving vitamin C and other quality properties of the freeze‑ and oven‐dried KP powder samples, respectively. CONCLUSION: The results obtained are important for the KP industry, including Indigenous enterprises, in selecting the most appropriate drying method for KP fruit in terms of quality and sustainability. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

[Display omitted] • Sesame oil (SO) oxidation promoted DPPH scavenging activity and MR browning. • MR (Lys-Glc) reduced SO oxidation, the loss of γ-tocopherol, and increased sesamol. • MR-lipid interaction increased alkylpyrazines, alkylfurans, and MR-derived ketones. • MR-lipid interaction reduced aliphatic furans, aldehydes, and some pyrazines. • MR-lipid interaction improved the nutty, roasted, fatty, and sweet aromas of SO. The formation mechanism behind the sophisticated aromas of sesame oil (SO) has not been elucidated. The interaction effects of the Maillard reaction (MR) and lipid oxidation on the aroma formation of fragrant sesame oil were investigated in model reaction systems made of l -lysine (Lys) and d -glucose (Glc) with or without fresh SO (FSO) or oxidized SO (OSO). The addition of OSO to the Lys-Glc model increased the MR browning at 294 nm and 420 nm and enhanced the DPPH radical scavenging activity greater than the addition of FSO (p < 0.05). The presence of lysine and glucose inhibited the oxidation of sesame oil, reduced the loss of γ-tocopherol, and facilitated the formation of sesamol (p < 0.05). The Maillard-lipid interaction led to the increased concentrations of some of the alkylpyrazines, alkylfurans, and MR-derived ketones and acids (p < 0.05) while reducing the concentrations of other pyrazines, lipid-derived furans, aliphatic aldehydes, ketones, alcohols, and acids (p < 0.05). The addition of FSO to the MR model enhanced the characteristic roasted, nutty, sweet, and fatty aromas in sesame oil (p < 0.05), while excessive lipid oxidation (OSO) brought about an unpleasant oxidized odor and reduced the characteristic aromas. This study helps to understand the sophisticated aroma formation mechanism in sesame oil and provides scientific instruction for precise flavor control in the production of sesame oil. [ABSTRACT FROM AUTHOR]

Non-enzymatic browning develops in dry-cooked foods and those with high carbohydrate develop acrylamide, a neurotoxin and potential carcinogen. However, some non-enzymatic browning products have reducing properties. We hypothesized that non-enzymatic browning and reducing power, a measure of antioxidant activity, of processed yam are affected by pre-treatment. Peeled yam cultivars (KM, RKD and SO89) in chunks were pre-soaked (0, 3, 6, 12, 18, and 24 h) in distilled water or pre-blanched (0, 1, 2, 3, 4, and 5 min) in steam. Pre-treated samples were deep-fried at 180 °C for 15 min or roasted at 220 °C for 30 min. Soluble solids, titratable acidity and pH of yam tissues and soaking water were determined. pH of the soaked yam tissues showed a positive relation with non-enzymatic browning. Pre-soaked fried KM and roasted RKD showed a significant decrease in non-enzymatic browning intensities. The reducing power of the cooked yams ranged between 78.94 and 185.92 % of ascorbic acid, and was affected by the different pre-treatment and dry-cooking methods.

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Drying due to the adverse physical and chemical changes is one of the most difficult processes in the food industry, especially to produce garlic powder. In this study, in order to avoid the Maillard reaction, garlics were pretreated by 0.5% sodium metabisulfite, 10% NaCl and citric acid (up to pH = 4) solutions. For this purpose, first, fresh garlic, after preparation according to the usual industrial method, was immersed in the pretreatment solution for 2 minutes at room temperature. The treated garlic was dried using cabinet method at 80 °C and 90 °C to achieve 5.2% water content, and then stored for 60 days at room temperature to evaluation of some quality characteristics including moisture content, vitamin C content, browning level, flavonoid content and pH. Based on the obtained results, moisture content did not change significantly in all treatments during storage. Control sample (without pretreatment) had had the highest off color and browning. Flavonoid and vitamin C contents were reduced in pretreated samples due to their solubility in water. Generally, based on the obtained results, garlic powder produced by pretreatments had lighter color than control sample which could increase their market acceptance and pretreatment with salt had highest effect in the production of garlic powder with a suitable color. [ABSTRACT FROM AUTHOR]

BACKGROUND Non‐enzymatic browning (NEB) is the main quality defect in shelf‐stable orange juice and other fruit juices during storage. Previous studies on NEB focused solely on the soluble fraction of orange juice, regardless of the fact that both soluble and insoluble fractions turn brown during extended storage. Clear evidence of the relative contribution of both fractions to NEB is currently lacking in the literature. This study investigated the contribution of the soluble and insoluble fractions of orange juice, which were obtained by centrifugation and ethanol precipitation, to NEB during storage. Changes in different NEB‐related attributes, such as ascorbic acid (AA) degradation, and the browning index (BI), were quantified and kinetically modeled. RESULTS: Evaluation of color during storage showed that the orange juice and the soluble compound‐containing fractions turned brown whereas the insoluble fractions did not. The soluble compound‐containing fractions showed exactly the same browning behavior with storage as the plain orange juice. Based on the kinetic parameters obtained, the degradation of AA, the hydrolysis of sucrose, the increase in the glucose and fructose content, and the formation of furfural and 5‐hydroxymethylfurfural during storage were similar for the plain orange juice and the soluble compound‐containing fractions. CONCLUSION: This work provided evidence that the soluble fraction of orange juice plays the major role in NEB, unlike the insoluble fraction, which seems to make no contribution. Results from this work also demonstrate the potential use of the soluble fraction as an orange‐juice‐based model system of reduced complexity that can be used for the further investigation of NEB processes. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Lipid oxidation progress in semi-dried shrimp (Acetes chinesis) products during cold storage was studied. Samples with low salt content and without vacuum package exhibited the highest level of lipid oxidation and browning development. High salt content samples showed lower TBARS and 1-penten-3-ol concentration during whole storage period than low salt samples. Vacuum package showed some effects in retarding lipid oxidation particularly for low salt content sample. Vacuum package could also preserve astaxanthin at the end of storage. Browning development in this semi-dried shrimp product during storage was not due to astaxanthin loss. The mechanism of the browning requires further investigation. [ABSTRACT FROM AUTHOR]

The effect of pressure (0.1, 15, 50 and 100 MPa) and temperature (43, 53, 63 °C) on the formation rate (k) of Maillard α-dicarbonyls (absorbance at 294) and melanoidins (absorbance at 420 nm), was studied during hyperbaric storage (HS) of glucose-glycine model solutions (pH 6). While increasing storage temperature increased k values according to the Arrhenius equation (E a ~ 85 kJ mol−1), increasing pressure decreased reaction rates as predicted by the Eyring model (V a ~ 11 mL mol−1). Pressure did not affect reaction temperature sensitivity, indicating no significant mechanism changes under hyperbaric conditions. A combined model predicting the effect of concomitant changes of temperature and pressure on Maillard reaction rate was implemented and validated within and outside (20–25 °C, 20–200 MPa) its building range. Results indicate HS to limit Maillard browning in food, with possible practical applications, and the potential to develop predictive models based on temperature-accelerated HS trials. The capability of hyperbaric storage to impair Maillard reaction rate extends the scope of this multi-tasking technology to the prevention of color alterations due to non-enzymatic browning. The latter is expected to be of industrial relevance in the case of perishable foods affected by this phenomenon, such as thermally-treated milk. In these matrices, the technology could concomitantly guarantee microbiological safety, protein functionalization, and Maillard browning impairment. • The effect of hyperbaric storage (HS) on Maillard reaction kinetics was studied. • Glucose-glycine solutions (pH 6) were selected as model systems and subjected to HS. • HS impaired α-dicarbonyls and melanoidins formation rate according to Eyring equation. • Pressure reduced the Arrhenius frequency factor without affecting activation energy. • A combined Arrhenius-Eyring model was developed to predict Maillard reaction rate. [ABSTRACT FROM AUTHOR]

This research examined the changes of black garlic (BG) quality attributes when raw materials of different initial moisture contents (iMC) were used. Fresh garlic bulbs (cv. Thai) were shade-dried for eight weeks at a controlled condition at 29 °C and relative humidity (RH) of 55% to the desired iMC (ranging from ca. 50–70%). BG processing was at 75 °C, RH = 80% for ten days. After processing, physiological characteristics and chemical properties of garlic were determined. Results illustrated that fresh garlic with higher moisture content (ca. 70%) resulted in BG of a dark brown colour, sloppy texture, and lesser acidity (pH = 4.44), while samples with lower iMCs (

• Maillard and sugar pyrolysis caused browning of vinegar soaked-soybean solution (VSS). • A glycine-fructose-gallic acid (GFG) model was proposed for browning in VSS solution. • 5-Hydroxymethylfurfural (5-HMF) formation in GFG model was a first-order reaction. • Browning rate and 5-HMF production were accelerated by acetic acid and iron ions. Non-enzymatic browning of vinegar soaked-soybean residual solution was investigated using a model solution. A glycine-fructose-gallic acid model system was proposed by analyzing reducing sugars, amino acids, total phenolics, and pH value of the vinegar soaked-soybean residual solution. Based on the proposed model, the kinetics of 5-hydroxymethylfurfural (5-HMF) formation was also studied. The results showed that Maillard reaction and sugar pyrolysis might be the accurate mechanisms of non-enzymatic browning in vinegar soaked-soybean residual solution. The formation of 5-HMF in the model solution exhibited characteristics of the first-order kinetic model at temperature from 60 to 140 °C. The frequency constant k f was 450.65 /h, and the apparent activation energy E a was 20.15 kJ/mol. Acetic acid, Fe2+, and Fe3+ significantly enhanced the browning rate and 5-HMF formation; whereas Ca2+, Mg2+, Na+, glucose oxidase, and H 2 O 2 inhibited the browning rate. [ABSTRACT FROM AUTHOR]

This study investigated the effect of air temperature, microwave power, and pomace thickness on the drying kinetics and quality of dried carrot pomace. The study established that the drying of carrot pomace occurs in the falling rate period, suggesting that drying was driven by molecular diffusion. The microwave-drying moisture diffusivity increased with microwave power and ranged between 1.57×10-8 and 2.61×10-8 m2/s. As regards convective air-drying, the moisture diffusivity values were between 3.38×10-10 and 8.27×10-10 m2/s. The microwave powerto-mass activation energy was 15.079W/g for 5 mm, 7.599 W/g for 10 mm and 9.542 W/g for 15 mm dried samples. Meanwhile, the temperature-dependent activation energy for carrot pomace was found to be 27.637 kJ/mol for 5 mm, 17.92 kJ/mol for 10 mm and 38.76 kJ/mol for 15 mm thickness pomace. Generally, drying time decreased with increasing microwave power or air temperature. The ascorbic acid content of the fresh carrot pomace reduced after both microwave and convective air-drying. However, microwave power, and sample thickness had significant effect on the ß-carotene content of dried products but air temperature did not have a significant effect. The effect of temperature and sample thickness on brown pigment formation was substantial with air temperature compared to microwave. The study has demonstrated that microwave drying, compared to conventional drying, enhances moisture removal, drying time, and preservation of carotenoids and ascorbic acid. Therefore, microwave drying can be considered as an alternative method for obtaining quality dried carrot pomace. [ABSTRACT FROM AUTHOR]

• Non-enzymatic browning widely occurs in wine during and after vinification. • Mechanisms of non-enzymatic browning induced by monomeric flavan-3-ols are reviewed. • Chromatic features and contribution of various xanthylium derivatives are discussed. • Factors that influence non-enzymatic browning in wine are summarized. • Insights into the complete reaction pathways of non-enzymatic browning are still lacking. Non-enzymatic browning occurs widely in both white and red wines, and it has a huge impact on the color evolution and aging potential. Previous studies have proved that phenolic compounds, especially those with catechol groups, are the most important substrates involved in browning reactions of wine. This review focus on the current knowledge of non-enzymatic browning in wine resulting from monomeric flavan-3-ols. First, some relevant aspects of monomeric flavan-3-ols are introduced, including their structures, origins, chemical reactivities, as well as potential impacts on the organoleptic properties of wine. Second, the mechanism for non-enzymatic browning induced by monomeric flavan-3-ols is discussed, with an emphasis on the formation of yellow xanthylium derivatives, followed by their spectral properties and effects on the color change of wine. Finally, attentions are also be given to the factors that influence non-enzymatic browning, such as metal ions, light exposure, additives in winemaking, etc. [ABSTRACT FROM AUTHOR]

• Grain phenolic profile has major effect on Maillard reactions and products. • Proanthocyanidins (PA) are strong inhibitors of Maillard reaction products formation. • Heat depolymerized reactive PA carbocations trap furan Maillard intermediates. • PA and flavones suppress melanoidin and volatile flavor compounds formation. • Whole-grain formulations may benefit from added Maillard reactive ingredients. Maillard reaction products (MRP) contribute to sensory quality of various foods. Whole grains (WG) are rich in phenols which may influence Maillard reaction pathways during thermal processing and impact WG product sensory attributes. This study investigated how WG phenolic profile affects MRP formation. Amylase-hydrolyzed wheat (white and red) and sorghum (white, red, tannin) brans were hydrothermally processed at 150 °C/6 min, and characterized for MRP using colorimetry, fluorescence spectroscopy, HPLC-MS/MS, and HS-SPME/GC–MS. Bran phenolic structure, and to a lesser extent content, had larger influence on MRP formation than protein/amino acid profile. Polymeric tannins (both in situ and when added to wheat brans) strongly inhibited volatile and non-volatile MRP intermediates and melanoidin formation, likely via their carbocation depolymerization intermediates trapping furans. Principle component analysis demonstrated clear segregation of volatiles formation based on bran phenolic profile. Phenolic composition should be considered in WG product formulation and processing to achieve desired MRP formation. [ABSTRACT FROM AUTHOR]

The browning of Dongbei Suancai (DS) is common during storage. To study the regulation mechanism of gamma (γ) irradiation on non-enzymatic browning in DS during storage, different doses of 0, 0.5, 1.5, and 2.5 kGy were used to irradiate DS , and the changes in contents of vitamin C (VC), polyphenol, reducing sugar, amino nitrogen, and 5-hydroxymethylfurfural (5-HMF) were investigated. The main factors and interaction of different irradiation doses on non-enzymatic browning were studied by path analysis. The results showed that 1.5 kGy irradiation inhibited the browning by reducing the oxidative decomposition of VC and decreasing its leading role in browning. And 2.5 kGy irradiation aggravated browning due to inducing the oxidative polymerisation of polyphenols and enhancing the decisive effect of polyphenols on browning. Therefore, 1.5 kGy irradiation was an effective measure with which to inhibit non-enzymatic browning in DS during storage. The present work provides a theoretical basis for effective regulation of browning in DS during storage. • 0.5 kGy irradiation had no significant effect on DS non-enzymatic browning. • 1.5 kGy irradiation inhibited browning by reducing the dominant effect of VC. • 2.5 kGy irradiation aggravated browning due to enhanced action of polyphenols. • Maillard reaction of reducing sugar and amino nitrogen was unaffected by irradiation. [ABSTRACT FROM AUTHOR]

Non-centrifugal cane sugar (panela) is an unrefined sugar obtained through intense dehydration of sugarcane juice. Browning, antioxidant capacity (measured by ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assay and total phenolic content) and the formation of acrylamide and other heat-induced compounds such as hydroxymethylfurfural (HMF) and furfural, were evaluated at different stages during the production of block panela. Values ranged between below the limit of quantitation (LOQ)–890 µg/kg, < LOQ–2.37 mg/kg, < LOQ–4.5 mg/kg, 0.51–3.6 Abs 420 nm/g, 0.89–4.18 mg gallic acid equivalents (GAE)/g and 5.08–29.70 µmol TE/g, for acrylamide, HMF, furfural, browning, total phenolic content and ABTS (all data in fresh weight), respectively. Acrylamide significantly increased as soluble solid content increased throughout the process. The critical stages for the formation of acrylamide, HMF and furfural were the concentration of the clarified juice in the concentration stage to get the panela honey and the final stage. Similar trends were observed for the other parameters. This research concludes that acrylamide, HMF and furfural form at a high rate during panela processing at the stage of juice concentration by intense evaporation. Therefore, the juice concentration stage is revealed as the critical step in the process to settle mitigation strategies.