Formation of volatile compounds from lycopene by autoxidation in a model system simulating dehydrated foods

Comprehensive two-dimensional gas chromatography-time of flight mass spectrometry as a tool for tracking roasting-induced changes in the volatilome of cold-pressed rapeseed oil

The aim of this study was to track changes in the volatilome of cold-pressed oil and press cakes obtained from roasted seeds and to combine it with the profile of non-volatile metabolites in a single study, in order to understand pathways of volatile organic compound (VOC) formation caused by thermal processing. Comprehensive two-dimensional gas chromatography-time of flight mass spectrometry was used for the analysis of VOCs in cold-pressed oils and corresponding press cakes obtained after roasting of seeds at 140 and 180 °C prior to pressing. Contents of primary metabolites (amino acids, saccharides, fatty acids) as well as selected secondary metabolites (glucosinolates, polyphenols) were determined, as many of them serve as precursors to volatile compounds formed especially in thermal reactions. After roasting, the formation of Maillard reaction products increased, which corresponded to the reduction of free amino acids and monosaccharides. Moreover, levels of the products of thermal oxidation of fatty acids, such as aldehydes and ketones, increased with the increasing temperature of roasting, although no significant changes were noted for fatty acids. Among sulphur-containing compounds, contents of the products and intermediates of methionine Strecker degradation increased significantly with the increasing temperature of roasting. Degradation of glucosinolates to nitriles occurred after thermal treatment. The results of this study confirmed that seed roasting before cold pressing has a significant effect on the volatiles, but also indicated roasting-induced changes in non-volatile metabolites of oil and press cake. Such an approach helps to understand metabolic changes occurring during rapeseed processing in cold-pressed oil production.

VOCs Analysis of Three Different Cultivars of Watermelon (Citrullus lanatus L.) Whole Dietary Fiber

In this study, the trend of VOCs of dietary fiber samples, coming from three different watermelon cultivars Citrullus lanatus L. (variety Gavina^®®, Crimson Sweet, and Asahi Miyako) was investigated. This foodstuff, obtained as a by-product of residual agri-food production, has gained increasing attention because of its many bioactive components and high dietary fiber content. The result is a fibrous material for specific applications in food manufacturing, such as corrector for some functional and technological properties. In this study, a method based on headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used to characterize the aromatic profiles of the dried raw materials. Therefore, the VOCs of the samples of the three cultivars were investigated. Experimental results have shown that watermelon fibers generate VOCs, which can be grouped into six common classes of analytes. The different distributions of the identified compounds made it possible to effectively differentiate the three cultivars studied based on their peculiar aroma profiles. In particular, Gavina^®® fiber is distinguished by the high content of terpenes, Asahi Miyako by the presence of aldehydes generated as fatty acid metabolites, and Crimson Sweet by the higher content of acetyl esters.

Coffee Roasting and Extraction as a Factor in Cold Brew Coffee Quality

Due to the dynamic growth of the cold brew coffee market, the aim of this study was to identify and characterize main bioactive and aromatic compounds that may be helpful for quality control during the production of popular beverages. Using headspace solid-phase microextraction and GC-MS and LC-MS analysis, prepared cold brew coffee extracts were investigated and compared with different green bean roasting profiles and varying extraction temperature and time parameters. In terms of quantitative composition, the study showed that cold brew coffees are an exceptional source of chlorogenic acid. Therefore, they may change consumers purchasing decisions on the beverage market and establish a new and natural substitute for controversial energy drinks. The analyses confirm the possibility of producing a beverage with increased chlorogenic acid content above 900 mg/L or at a similar level of 400–500 mg/L with caffeine, which may be important on an industrial scale due to the possibility of diversifying beverage production. Furthermore, aroma compounds were presented as markers responsible for fruity or caramel–roasted-almond notes and changes in their concentrations according to the recipe were also presented. The best option for cold brew coffee production appears to be beans roasted in the 210–220 °C temperature range.

Oxidative stability of extra-virgin olive oil enriched or not with lycopene. Importance of the initial quality of the oil for its performance during in vitro gastrointestinal digestion

The performance of commercial non-enriched and lycopene-enriched extra-virgin olive oils (EVOO) during in vitro gastrointestinal digestion was studied in order to elucidate potential benefits of lycopene addition. Samples were analyzed before and after digestion by Proton Nuclear Magnetic Resonance (¹H NMR) and Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS). EVOO samples differed in both main (oleic and linoleic acyl groups) and minor components (phenolic and oxidation compounds). Regardless of the presence of lycopene, all the samples reached a high degree of lipolysis and showed high stability towards oxidation under digestion conditions. Rather than oxidation reactions, the hydroperoxides initially present in the oil were reduced to more stable hydroxides. Likewise, hydroxy-diene isomerization from cis,trans to trans,trans occurred. Hence, the presumed antioxidant effect of lycopene was not noticed during in vitro digestion of EVOO. Similar experiments carried out with a more polyunsaturated oil (sunflower oil) indicated that lycopene slowed down the advance of oxidation slightly. However, in the case of EVOO, its initial quality prevailed over the slight antioxidant effect exerted by lycopene at the concentration present in commercial samples, determining the oxidation compound profile of the digests.

Chemical Stability of Lycopene in Processed Products: A Review of the Effects of Processing Methods and Modern Preservation Strategies

Lycopene, one of the most dominant carotenoids in a person's diet, is a well-known natural compound that has protective effects against chronic diseases. Industrial and domestic processing and storage conditions significantly influence retention and isomerization of lycopene; thus, in recent years, great attention has been given for their preservative effects of lycopene. This review highlights recent strategies that have been developed to preserve lycopene in processed products, especially in tomato pulp, puree, paste, and juice. The key factors influencing lycopene degradation and isomerization, such as ingredients and intensity of thermal treatments, are also discussed. Special attention was paid to the crystalline structures of lycopene which facilitate its resistance to degradation and isomerization. Emerging non-thermal processing methods, such as ultrasound and high-pressure processing (HPP), are critically evaluated for their preservation of thermo-labile compounds. Novel trends to improve lycopene stability by micro- and nanoencapsulation and addition of antioxidants are also included to examine their efficacy to protect against light, heat, oxygen, and other oxidative processes. Finally, recommended processing and storage conditions are discussed to provide strategies to retain the highest possible amount of bioactive lycopene until consumption.

A kinetic study of carotenoid degradation during storage of papaya chips obtained by vacuum frying with saturated and unsaturated oils

The aim of the study was to evaluate the degradation kinetics of carotenoids (CTs) in vacuum-fried papaya (Carica papaya L.) chips (PCs) during storage at four temperatures (15, 25, 35 and 45 °C) for 52 and 94 days for the two highest and lowest temperatures, respectively. Three treatments were applied to obtain the chips: chips with soy oil (24% lipids) and chips with palm oil (24% and 29% lipids). All the chips were packaged under air or nitrogen conditions. The CTs analyzed by HPLC-DAD were per order of content all-E-lycopene (LYC), Z-lycopene (Z-LYC), all-E-β-carotene (BC), all-E-β-cryptoxanthin (BCX) and Z-β-carotene (Z-BC). The all-E-forms represented 80% of carotenoids in PCs. No significant carotenoid degradation was observed in the PCs packaged under nitrogen conditions during storage. For chips stored under air conditions, a second-order kinetic model best fitted the experimental data. Rate constants for LYC degradation were the lowest, while BCX and BC presented similar rate constants 4-23-fold higher depending on lipid composition. All Z-isomers degraded faster than all-E-forms, but Z-BC degraded only 2-4-fold faster than Z-LYC. All CTs followed Arrhenius temperature-dependency pattern and LYC showed the lowest activation energies (5-21 kJ/mol). A higher lipid content in the chips with palm oil enhanced the carotenoid retention in PCs. Moreover, a greater retention (p < 0.05) of CTs was observed in PCs with soy oil. The use of soy oil instead of palm oil increased the theoretical half-life (at 25 °C) by 2.2, 1.3 and 5.9-fold for BCX, BC and LYC, respectively. Packaging under nitrogen conditions and lipid composition may be considered to optimize the shelf life and carotenoid retention in PCs during storage.

Update on natural food pigments - A mini-review on carotenoids, anthocyanins, and betalains

Extensive structure elucidation has revealed a remarkable diversity of structures for carotenoids, anthocyanins, and betalains, the major natural pigments in plant-derived foods. Composition, stability, influencing factors, processing effects have been widely investigated. Carotenoids isomerize and oxidize while anthocyanins undergo hydrolysis, nucleophilic attack of water, ring fission, and polymerization during thermal processing. Betacyanins suffer deglycosylation, isomerization, dehydrogenation, hydrolysis, and decarboxylation. Biotechnological production dominates research on carotenoids as food colorants while the search for plant sources continues with anthocyanins and betalains. Stabilization studies presently focus on microencapsulation and nanoencapsulation. For anthocyanins, co-pigmentation has also been intensely researched. Carotenoids have been the most studied in terms of health effects, involving epidemiological, cell, animal, and human intervention studies, yet some inconsistencies in the results persist. A wide range of biological activities have been attributed to anthocyanins and betalains, based mainly on cell and animal studies; human clinical studies are lacking.