Characterization of the Key Aroma Constituents in Fry Breads by Means of the Sensomics Concept

Research progress in the synthesis of stable isotopes of food flavour compounds

Stable isotope dilution analysis (SIDA) is a quantitative method widely used in the determination of food flavour components because of its high efficiency and precision. However, many stable isotope reagents cannot be purchased through commercial channels. In this paper, the basic principle of stable isotope dilution analysis is introduced and its historical progress in food flavour analysis are examined. Then, the preparation methods of stable isotope analysis of food flavour compounds in recent years were compiled. In the literature reviewed, from 2012 to 2022, there were 185 stable isotopes of food flavour compounds used for food flavour analysis, of which 126 compounds can be purchased commercially and 59 compounds must be prepared in the laboratory. This review aims to present the methods used in the synthesis of stable isotopes to facilitate the development of food flavour analysis using stable isotope technology.

Coconut oil as an alternative to butter and shortening in bread making

The characteristics of bread prepared with coconut oil were investigated to determine whether it can be used as an alternative to butter and shortening. Loaf height of the bread increased by adding butter and shortening water content of bread containing oils and fats was lower than that without oils and fats, and baking loss increased with decreasing water content. The addition of oils and fats influenced the baking color of bread and hindered the hardening of bread samples over time. Moreover, the addition and type of oils and fats influenced the crust density of bread samples and dough expansion. Furthermore, numerous fine bubbles were present in bread samples without oils and fats, whereas the size and number of bubbles increased and decreased in bread samples containing oils and fats, respectively. The band concentrations of insoluble proteins at approximately 39, 41, and 48 kDa in freeze-dried bread samples without oils and fats were significantly lower than those containing oils and fats. Thirty volatile compounds were detected in all bread samples tested, and the number was high in the following order: bread samples with butter, shortening, and coconut oil, and without oils and fats. However, sensory evaluation showed no significant differences among all bread samples tested. Therefore, it was suggested that bread containing coconut oil had the same characteristics as that containing butter and shortening. PRACTICAL APPLICATION: Butter and shortening are usually used in bread making, although bread prepared with coconut oil can possess the same characteristics as that containing them. Therefore, this study evaluated the characteristics of bread prepared with coconut oil and revealed that use of coconut oil enabled a vegan bread with reduced environmental impact because coconut oil is a vegetable-derived oil that does not require the cutting of tropical rainforests.

Effect of Frying Process on the Flavor Variations of Allium Plants

The Allium plant is widely used in cuisines around the world for its characteristic flavor. The general profile of the plant changes a lot and presents quite different smells after the frying process. In this work, five Allium plants and their fried oils were compared to find out how the frying process impacts the general flavor profile. The results of sensory analysis indicated that the frying process could substantially increase the flavor acceptability of fresh Allium plants. Meanwhile, according to gas chromatography-mass spectrometry (GC-MS) analysis, fewer volatile compounds were detected in fresh Allium plants than in their fried oils. Furthermore, contents of nitrogen-containing compounds (ranging from 0.17 μg/g to 268.97 μg/g), aldehydes (ranging from 71.82 μg/g to 1164.84 μg/g), and lactones (ranging from 0 μg/g to 12.38 μg/g) increased significantly. In addition, more aroma-active substances were identified in the fried Allium oils revealed by gas chromatography-olfactometry (GC-O) analysis. Sulfur-containing compounds were the most abundant in fresh Allium plants, whereas nitrogen-containing compounds dominated in fried oils. The thermal degradation of sugars, amino acids and lipids as well as interactions between carbohydrates, proteins, and fats during the frying process were thought to be the main contributors to these variations. Therefore, this research provides a theoretical basis for the quality control of onion oil flavor and promotes the further development of the onion plant industry. Consequently, the research provided a theoretical basis for the quality control of Allium oils' flavor and promoted the further development of Allium plant industries.

Aroma Clouds of Foods: A Step Forward to Unveil Food Aroma Complexity Using GC × GC

The human senses shape the life in several aspects, namely well-being, socialization, health status, and diet, among others. However, only recently, the understanding of this highly sophisticated sensory neuronal pathway has gained new advances. Also, it is known that each olfactory receptor cell expresses only one type of odorant receptor, and each receptor can detect a limited number of odorant substances. Odorant substances are typically volatile or semi-volatile in nature, exhibit low relative molecular weight, and represent a wide variety of chemical families. These molecules may be released from foods, constituting clouds surrounding them, and are responsible for their aroma properties. A single natural aroma may contain a huge number of volatile components, and some of them are present in trace amounts, which make their study especially difficult. Understanding the components of food aromas has become more important than ever with the transformation of food systems and the increased innovation in the food industry. Two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC-ToFMS) seems to be a powerful technique for the analytical coverage of the food aromas. Thus, the main purpose of this review is to critically discuss the potential of the GC × GC-based methodologies, combined with a headspace solvent-free microextraction technique, in tandem with data processing and data analysis, as a useful tool to the analysis of the chemical aroma clouds of foods. Due to the broad and complex nature of the aroma chemistry subject, some concepts and challenges related to the characterization of volatile molecules and the perception of aromas will be presented in advance. All topics covered in this review will be elucidated, as much as possible, with examples reported in recent publications, to make the interpretation of the fascinating world of food aroma chemistry more attractive and perceptive.

Characterization of the Key Aroma Constituents in Fried Tilapia through the Sensorics Concept

The object of this study was tilapia fish that were fried in soybean oil. Volatile compounds were extracted from the fish by ASE-HVE and were studied by GC-O-MS and the AEDA analysis method. A total of 30 aroma compounds were initially determined, and these compounds contribute to the aroma of fried tilapias. The key volatile compounds in fried tilapia were quantitatively analyzed by GC-MS, and the volatile compounds in soybean-fried tilapia were studied by flavor recombination and deletion experiments. Trimethylamine, hexanal, 2,3-dimethylpyrazine, dimethyl trisulfide, trans-2-octenal, 2,3-dimethyl-5-ethylpyrazine, (E)-2-nonenal, 2-propyl-pyridine, and (E,E)-2,4-decadienal were finally determined to be the key volatile compounds in soybean-fried tilapia.