Influence of drying technologies on the aroma of Sicilian red garlic

Profiles of volatile sulfur compounds in various vegetables consumed in Korea using HS-SPME-GC/MS technique

Volatile sulfur compounds (VSCs) are not only important for their therapeutic potential but also significantly influence the flavor profiles of agricultural products. VSCs exhibit various chemical structures due to their stability and volatility, and they may form or be altered as a result of enzymatic and chemical reactions during storage and cooking. This study has focused on profiles of VSCs in 58 different vegetable samples by using HS-SPME-GC/MS technique and chemometric analyses. The validation was carried out using cabbage juice as a vegetable matrix for VSCs analysis, showing satisfactory repeatability (RSD 8.07% ~ 9.45%), reproducibility (RSD 4.22% ~ 7.71%), accuracy and specificity. The established method was utilized on various vegetables, revealing that 21 VSCs such as sulfides, disulfides, trisulfides, isothiocyanates, sulfhydryls, and thiophenes were successfully identified and quantified. These compounds were found in a range of vegetables including Allium species, Cruciferae, Capsicum species, green leafy vegetables, and mushrooms. In particular, isocyanate and allyl groups were abundant in Cruciferae and Allium vegetables, respectively. Cooking conditions were shown to reduce the levels of certain sulfur compounds such as dimethyl sulfide and dimethyl trisulfide in vegetables like broccoli and cabbage, suggesting that heat treatment can lead to the volatilization and reduction of these compounds. The present study provides reliable insights into the compositions of VSCs in various vegetables and examines the changes induced by different cooking methods.

New insights on low-temperature storage regulating garlic greening and the accumulation of pigment precursors via glutathione metabolism and energy cycles

To explore regulation mechanism of temperature on garlic greening and pigment precursors' accumulation, greening capacities, pigment precursors and critical metabolites, enzyme and genes involved in glutathione and NADPH metabolism of garlic stored at five temperatures (4, 8, 16, 24 and 30 ℃) were analyzed. Results showed that garlic pre-stored at 4, 8 and 16 ℃ were more likely to green than ones at 24 and 30 ℃ after pickling. After 25 days, more S-1-propenyl-l-cysteine sulfoxide (1-PeCSO) were detected in garlic stored at 4, 8 and 16 ℃ (753.60, 921.85 and 756.75 mAU, respectively) than that at 24 and 30 ℃ (394.35 and 290.70 mAU). Pigment precursors' accumulation in garlic was mainly realized by glutathione and NADPH metabolism under low-temperature storage, through enhancements of activities or expressions for GR (GSR), GST (GST), γ-GT (GGT1, GGT2), 6PGDH (PGD) and ICDHc (IDH1). This study enriched the mechanism of garlic greening.

Innovative Process for Dried Caper (Capparis spinosa L.) Powder Production

This research aimed to develop a new time, energy, and cost-saving production process for obtaining dried powder from Capparis spinosa floral buds. Four different trials, including dry salting with 40% NaCl (for 10 days and 40 days) and brine salting with 18% NaCl (at room temperature for 3 days and at 60 °C for 6 h), were carried out, and two different air-drying temperatures (40 and 50 °C) were used. The effects on chemical and sensory characteristics were investigated and compared with traditional undried caper samples. Spectroscopy and chromatographic techniques such as UV-VIS, GC-MS, and FTIR were used for chlorophylls, carotenoids, polyphenols, flavonoids, and volatile aroma compounds' analyses. Moreover, a sensory descriptive analysis and acceptability were applied to individuate the product most appreciated by the consumers. Among the different trials, brine salting at 60 °C and drying at 50 °C constituted the fastest process that yielded an appreciated powder by consumers; the chemical analyses demonstrated that this process did not lead to the formation of extraneous aroma compounds that could influence the typical sensory properties of capers and maintained high levels of chlorophylls, carotenoids, and polyphenols. Altogether, the results could be of great significance to industrial production and potentiate positive impacts on the economy of production areas.

Influence of Different Frying Processes on the Flavor Characteristics and Sensory Profile of Garlic Oil

Fried garlic oil has been widely used in traditional Chinese cuisine and, recently, has become increasingly popular in food manufacturing. In this study, the effects of different initial and final frying temperature on the flavor characteristics and sensory profile of fried garlic oil were investigated using solvent-assisted flavor evaporation (SAFE) combined with gas chromatography–mass spectrometry (GC–MS). Results showed that the content of flavor compounds changed significantly as the frying temperature was increased. The sample that was treated at an initial temperature of 115 °C and a final temperature of 155 °C contained the highest amount of thioethers and heterocycles, mainly comprising dimethyl trisulfide, diallyl disulfide, and 2-vinyl-4H-1,2-dithiin. Partial least-squares regression elucidated the sensory attributes of fried and roasted garlic, showing a high correlation with thioethers and pyrazines. Furthermore, changes in the 2,6-dimethylpyrazine, dimethyl trisulfide, and diallyl disulfide concentrations were detected every 5 °C during the frying process (initial temperature, 115 °C; final temperature, 155 °C). Dimethyl trisulfide and diallyl disulfide concentrations showed irregular, downward trends, while 2,6-dimethylpyrazine concentration exhibited an increasing trend.

Effects of Ultrasound Technique on the Composition of Different Essential Oils

The objective of the experiment was to investigate the stability of the composition of selected essential oils in the model systems containing methanol and hexane solutions which were treated with ultrasound. Solutions of the oils, with a concentration of 90 mg/ml, were subjected to the effect of ultrasounds with a frequency of 20 kHz and an output power of 200 W for periods of 2 min and 10 min at 50% and 80% power. The experiment has shown no significant effect on the composition of the essential oils resulting from the applied parameters of the process in the tested model systems. The study indicates that the sonication parameters adopted in the experiment can be applied in the case of analogous systems containing essential oils in their composition.