Development of a novel Maillard reaction-based time–temperature indicator for monitoring the fluorescent AGE content in reheated foods

Molecular Characterization of Cooking Processes: A Metabolomics Decoding of Vaporous Emissions for Food Markers and Thermal Reaction Indicators

Thermal processing of food plays a fundamental role in everyday life. Whereas most researchers study thermal processes directly in the matrix, molecular information in the form of non- and semivolatile compounds conveyed by vaporous emissions is often neglected. We performed a metabolomics study of processing emissions from 96 different food items to define the interaction between the processed matrix and released metabolites. Untargeted profiling of vapor samples revealed matrix-dependent molecular spaces that were characterized by Fourier-transform ion cyclotron resonance-mass spectrometry and ultra-performance liquid chromatography-mass spectrometry. Thermal degradation products of peptides and amino acids can be used for the differentiation of animal-based food from plant-based food, which generally is characterized by secondary plant metabolites or carbohydrates. Further, heat-sensitive processing indicators were characterized and discussed in the background of the Maillard reaction. These reveal that processing emissions contain a dense layer of information suitable for deep insights into food composition and control of cooking processes based on processing emissions.

An Edible Humidity Indicator That Responds to Changes in Humidity Mechanically

Elevated humidity levels in medical, food, and pharmaceutical products may reduce the products' shelf life, trigger bacterial growth, and even lead to complete spoilage. In this study, we report a humidity indicator that mechanically bends and rolls itself irreversibly upon exposure to high humidity conditions. The indicator is made of two food-grade polymer films with distinct ratios of a milk protein, casein, and a plasticizer, glycerol, that are physically attached to each other. Based on the thermogravimetric analysis and microstructural characterization, we hypothesize that the bending mechanism is a result of hygroscopic swelling and consequent counter diffusion of water and glycerol. Guided by this mechanism, we demonstrate that the rolling behavior, including response time and final curvature, can be tuned by the geometric dimensions of the indicator. As the proposed indicator is made of food-grade ingredients, it can be placed directly in contact with perishable products to report exposure to undesirable humidity inside the package, without the risk of contaminating the product or causing oral toxicity in case of accidental digestion, features that commercial inedible electronic and chemo-chromatic sensors cannot provide presently.

Application of Molecular Transformer approach for predicting the potential reactions to generate advanced glycation end products in infant formula

Advanced glycation end products (AGEs) are associated with the occurrence of human chronic diseases, and exist commonly in thermally processed foods, such as infant formula. Existing research mainly focuses on the discrete simulation system, which is time-consuming and challenging, but accumulates of a large amount of valuable data. This study aimed to propose a specific Molecular Transformer-based model trained on the data curated from literature to predict the chemical reaction of AGEs, and apply it to infant formula to observe which new reactions could generate AGEs. The model achieved top-3 accuracy of 76.0% on the total dataset. Based on the model prediction results, five reactions were selected for experimental verification, and four of them were consistent with the model prediction results. This prospective study might potentially revolutionize the discovery of AGEs reactions and provide theoretical guidelines for designing a safer infant formula.

Glycine-Xylose Amadori Compound Formation Tracing through Maillard Browning Inhibition by 2-Threityl-thiazolidine-4-carboxylic Acid Formation from Deoxyosone and Exogenous Cysteine

The browning inhibition of cysteine on the Maillard reaction of glycine-xylose performed under stepwise increased temperature was investigated. The browning degrees of the final products prepared with cysteine addition at different time points were found dissimilar, and the addition time point of cysteine yielding the lightest browning products was consistent with the time when the glycine-xylose Amadori rearrangement product (GX-ARP) reached its maximum yield. To clarify the reason for browning inhibition caused by cysteine, the evolution of key browning precursors formed in the GX-ARP model with cysteine involved was investigated by HPLC with a diode array detector. The results on the browning degree of the thermal reaction products of GX-ARP with cysteine addition showed great inhibition of α-dicarbonyl generation, which resulted in a significant increase in the activation energy of GX-ARP conversion to browning formation during heat treatment. Strong evidence suggested that the additional cysteine got involved in GX-ARP degradation and reacted with the deoxyosones derived from GX-ARP to yield cyclic 2-threityl-thiazolidine-4-carboxylic acid (TTCA). TTCA formation shunted the degradation of deoxyosones into short-chain α-dicarbonyls, which were important browning precursors, and consequently inhibited the Maillard browning.

Formation mechanism of AGEs in Maillard reaction model systems containing ascorbic acid

The dietary advanced glycation end products (AGEs) contribute to the development of major chronic diseases. Maillard reactions are the main mechanism for AGEs formation but their formation involving ascorbic acid (AA) is far from being fully understood. This study investigated the effect of pH (6-10) and temperature (65, 100 and 120 ℃) on AGEs formation in three model systems: glucose (Glu) + lysine (Lys), AA + Lys and Glu + Lys + AA. In addition, the formation pathway of AGEs in Glu + Lys + AA model system was proposed by carbon module labeling (CAMOLA) technique. The results suggested alkaline environment can promote the production of N-carboxymethyllysine (CML) and N-carboxyethyllysine (CEL), but inhibit the production of pyrraline (Pyr). Meanwhile the high temperature favored AGEs formation. In the U-¹³C-Glu + Lys + AA model, AA produced glyoxal (GO), methylglyoxal (MGO), CML and CEL, which was significantly higher than with Glu alone. This study provides a theoretical basis for the formation mechanism of AGEs in the Maillard reaction involving AA.

Nanomaterials in Smart Packaging Applications: A Review

Food wastage is a critical and world-wide issue resulting from an excess of food supply, poor food storage, poor marketing, and unstable markets. Since food quality depends on consumer standards, it becomes necessary to monitor the quality to ensure it meets those standards. Embedding sensors with active nanomaterials in food packaging enables customers to monitor the quality of their food in real-time. Though there are many different sensors that can monitor food quality and safety, pH sensors and time-temperature indicators (TTIs) are the most critical metrics in indicating quality. This review showcases some of the recent progress, their importance, preconditions, and the various future needs of pH sensors and TTIs in food packaging for smart sensors in food packaging applications. In discussing these topics, this review includes the materials used to make these sensors, which vary from polymers, metals, metal-oxides, carbon-based materials; and their modes of fabrication, ranging from thin or thick film deposition methods, solution-based chemistry, and electrodeposition. By discussing the use of these materials, novel fabrication process, and problems for the two sensors, this review offers solutions to a brighter future for the use of nanomaterials for pH indicator and TTIs in food packaging applications.

Development of a time-temperature indicator based on Maillard reaction for visually monitoring the freshness of mackerel

Due to the highly cost-effective and maneuverable property, Maillard reaction-based time-temperature indicators (TTIs) are considered ideal devices for temperature track and quality indication. The objective of this study was to develop a cold-sensitive TTI based on the Maillard reaction reflecting the freshness of chilled seafood. Firstly, the color evolution trends of a series of Maillard reaction-based TTIs were investigated and the xylose-lysine group represented obvious color change. Fourier transform infrared (FTIR) spectroscopy revealed the color change was associated with the formation of CN bond in melanoidin. Simultaneously, the relationships of the color change of TTI with time and temperature were established. The activation energy value (Ea) of TTI was close to that of mackerel. There existed a good relevance (R² = 0.98) between the color change of TTI and the total volatile basic nitrogen content of mackerel, suggesting this novel TTI might have the potential to monitor the freshness of mackerel.

Review of the formation and influencing factors of food-derived glycated lipids

Glycated lipids are formed by a Maillard reaction between the aldehyde group of a reducing sugar with the free amino group of an amino-lipid. The formation and accumulation of glycated lipids are closely related to the prognosis of diabetes, vascular disease, and cancer. However, it is not clear whether food-derived glycated lipids pose a direct threat to the human body. In this review, potentially harmful effect, distribution, formation environment and mechanism, and determination and inhibitory methods of glycated lipids are presented. Future research directions for the study of food-derived glycated lipids include: (1) understanding their digestion, absorption, and metabolism in the human body; (2) expanding the available database for associated risk assessment; (3) relating their formation mechanism to food production processes; (4) revealing the formation mechanism of food-derived glycated lipids; (5) developing rapid, reliable, and inexpensive determination methods for the compounds in different foods; and (6) seeking effective inhibitors. This review will contribute to the final control of food-derived glycated lipids.