Optimization of roasting conditions of microwave roasted Pistacia terebinthus beans

Characterization of aroma compounds and effects of amino acids on the release of esters in Laimao baijiu

BACKGROUND

Laimao baijiu is a typical soy-sauce aroma-type baijiu in China. Amino acids are non-volatile compounds in baijiu and are beneficial to human health. Aroma is one of the important indicators that are used to evaluate the quality of baijiu. The interaction between aroma-active compounds and non-volatile compounds can also affect the release of aroma compounds. In this study, we identified the active-aroma compounds and amino acids in Laimao baijiu by stir bar sorptive extraction (SBSE), gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The interaction between amino acids and key esters was investigated by sensory analysis and partition coefficients.

RESULTS

A total of 63 aroma compounds and 21 amino acids were identified. Twenty-one esters were identified from them as major aroma-active ester compounds with odor activity values ≥ 1. Finally, sensory analysis revealed that l-alanine had a significant effect on the strength of the aromas of esters, suggesting that low concentrations of amino acids were more likely to promote the release of esters and high concentrations were more likely to inhibit this. The partition coefficient can be a good explanation for this phenomenon.

CONCLUSION

l-Alanine can significantly affect the aroma intensity of key ester aroma compounds in Laimao baijiu, and the effects of different concentrations of amino acids are different. This work shows that amino acids, as non-volatile compounds, have a regulatory effect on the release of aroma compounds in alcoholic beverages, which may provide new technical support for the aroma modulation of alcoholic beverages. © 2022 Society of Chemical Industry.

The effect of gamma irradiation, microwaves, and roasting on aflatoxin levels in pistachio kernels

Pistachio is the second largest non-oil export in Iran. The most important problem in pistachio export is its contamination with aflatoxin. Therefore, this study aimed to evaluate the effects of several physical and chemical methods on the qualitative, qualitative and sensory properties of pistachios from Iran as well as the associated residual aflatoxin levels. This study investigated the effects of roasting (temperature 120 °C for 20 and 40 min), gamma radiation (2.5 and 5 KGy), and microwave (1 and 2 min) methods on pistachios and their qualitative characteristics, including moisture, colour, and sensory properties. In addition, aflatoxin B1 and total aflatoxins were artificially added to pistachios to determine the level of aflatoxin remaining after chemical and physical methods. The results showed that the lowest residual level of aflatoxin B1 was related to combined microwave and irradiation methods. Further, the combined methods showed the lowest total aflatoxins residue so the lowest total aflatoxins residue after chemical contamination of 8 μg/kg aflatoxin was related to the combined methods of 5 KGy irradiations with 2 min of the microwave. In addition, the microwaved and irradiated samples did not differ significantly from the control samples in terms of sensory characteristics (P<0.05). It can be concluded that these methods can be successfully applied without adversely affecting the characteristics of pistachios. Considering the position of pistachios in domestic and global markets, these processes can be used to reduce aflatoxins, improve the quality of pistachios, and increase export.

Impact of different microwave treatments on food texture

Electromagnetic waves are frequently used for food processing with commercial or domestic type microwave ovens at present. Microwaves cause molecular movement by the migration of ionic particles or rotation of dipolar particles. Considering the potential applications of microwave technique in food industry, it is seen that microwaves have many advantages such as saving time, better final product quality (more taste, color, and nutritional value), and rapid heat generation. Although microwave treatment used for food processing with developing technologies have a positive effect in terms of time, energy, or nutrient value, it is also very important to what extent they affect the textural properties of the food that they apply to. For this purpose, in this study, it has been investigated that the effects of commonly used microwave treatments such as drying, heating, baking, cooking, thawing, toasting, blanching, frying, and sterilization on the textural properties of food. In addition, this study has also covered the challenges of microwave treatments and future work. In conclusion, microwave treatments cause energy saving due to a short processing time. Therefore, it can be said that it affects the textural properties positively. However, it is important that the microwave processing conditions used are chosen appropriately for each food material.

Effect of Microwave Treatment on Adzuki Beans (Vigna angularis L.) under Dry State—Analyzing Microstructure, Water Absorption, and Antioxidant Properties

In this study, a microwave was used on adzuki beans (Arari and Geomguseul) without water, in order to investigate their changes in microstructure, water absorption, and antioxidative properties. As the microwave treatment time increased (2450 MHz, 0 to 60 s), the lightness, redness, and yellowness were reduced, and moisture content significantly decreased in both varieties. The microstructure space between the seed coat, cotyledon, and pores within the cotyledon were observed, due to the loss of moisture. Regardless of microwave treatment, the water absorption behavior of the adzuki beans was sigmoidal. However, the water absorption kinetics of Arari increased after microwave treatment, whereas with microwave-treated Geomguseul, the water absorption rate decreased, compared to the control, except for the sample treated for 30 s. During soaking, the water absorption and softening rates in the microwave-treated adzuki bean were twice as fast as the untreated beans. Antioxidant activity, total phenolic compounds, and total flavonoid compounds were greatly improved by microwave treatment. These results indicate that microwave treatment affects the color, hydration, and bioactive compounds, and it can be used as a pretreatment method before processing adzuki beans.

Valorization of microwave roasted Tamarindus indica seed in functional biscuit production and effects on rheological and textural properties of biscuit dough

As one of the most popular bakery products, biscuits lack several nutrients such as fiber, protein, and some minerals. In this study, biscuits were enriched with T. indica seed flour. T. indica seeds were roasted by microwave at 600 W for 8, 16 and 24 min. Wheat flour was substituted by unroasted and roasted tamarind flour at level of 10%. Owing to its appreciated antioxidant activity, fiber and protein content, T. indica seed flour improved the nutritional value and antioxidative properties of biscuits. The fiber content of biscuits increased up to 3.88 ± 0.02% and protein content up to 11.22 ± 0.05 (p < 0.05). Moderately roasting process developed the sensory and antioxidative properties of T. indica seeds. Microwave roasting was used successfully for roasting T. indica seeds.

Effects of roasting conditions on Korean rice wine (Makgeolli) with licorice (Glycyrrhiza uralensis Fischer)

The present study investigated the effect of roasting process (temperature: 150, 180, and 210 °C; time: 10, 20, and 30 min) of licorice on the browning index (BI), total flavonoid content (TFC), and antioxidant activity for ingredient of Makgeolli. The antioxidant activity was measured by assaying DPPH radical scavenging activity (DPPH·IC₅₀) and Trolox equivalent antioxidant capacity (TEAC). In addition, the quality characteristics of Makgeolli with different amount (0%, 6%, 12%, and 18%) of roasted licorice extract (RLE) were measured comparison to un-roasted licorice extract (ULE). When superimposing the contour plots of the responses in which the limits of each response were determined, the optimum conditions for roasting licorice were 178 °C for 24 min. Moreover, results revealed that Makgeolli with 12% RLE under optimum roasting condition was superior with respect to antioxidant activity and more acceptable based on sensory properties than ULE.

Characterization of the major aroma-active compounds in peach (Prunus persica L. Batsch) by gas chromatography-olfactometry, flame photometric detection and molecular sensory science approaches

Aroma profiles and aroma-active compounds of "Yulu" peach from Fenghua (the peach known for the best flavor and quality in China) were investigated by headspace solid-phase microextraction (HS-SPME), solvent-assisted flavor evaporation (SAFE), gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and flame photometric detection (FPD). The combination of these methods improved the analysis and identification of aroma substances compared to the combination of a single aroma extraction method and GC-MS. A total of 85 aroma-active compounds, including 10 sulfur compounds were detected. Methional, methyl 3-(methylthio)propionate, methionol, and benzothiazole were first detected in peaches. These aroma compounds cannot only supplement the database of aroma substances of peaches, but also provide data support for traceability of the origins of "Yulu" peaches. In addition, the odor activity value (OAV) was used to identify the contributions of the most important compounds. The results indicated that hexanal, 3-methylbutanal, (E)-2-hexen-1-ol, 3-mercaptohexyl acetate, (E,E)-2,4-decadienal, 2-methylpropanal, γ-decalactone, 2-methylbutanal, theaspirane, and δ-decalactone were the key aroma-active compounds. The key characteristic aroma components were further ascertained by aroma reconstitution and omission experiments, which showed that the fruity, floral, sulfur, and sour notes could be well simulated. Finally, the perceptual interactions between different sulfur compounds and fruity recombination (FR) were explored. 3-mercaptohexanol and 4-methyl-4-mercaptopentan-2-one could significantly decrease the threshold of FR. The possible reason was that these two sulfur compounds had synergistic effects with the aroma compounds in FR, with the U model confirming the results of these synergistic effects. The perceptual interactions provide a basis for the regulation of characteristic fruity aroma of peach products.

Effects of waste fig seed powder on quality as an innovative ingredient in biscuit formulation

Being a rich source of antioxidants, phenolic compounds and dietary fiber, the fig seed could be valuable health-promoting food ingredient. The possibility of using fig seed powder in biscuits was investigated. For this purpose, wheat flour was replaced by fig seed powder at levels of 0, 5, 10, and 15%. The effects of replacement on proximate composition, color values, total phenolic contents, antioxidant activity, textural characteristics, and sensorial properties of biscuit samples were investigated. The composition of fig seed powder showed a significantly higher concentration of fiber (56.6 ± 0.27%), protein (14.32 ± 0.21%), fat (20.32 ± 0.32%), and total phenolic content (665.12 ± 0.52 mg GAE/100 g). The biscuit samples were obtained with increased fiber content by adding fig seed powder to the biscuit formulation. Moreover, fig seed powder increased the total phenolic content and antioxidant activity of biscuits significantly (P < 0.05). The addition of fig seed powder to the biscuit formulation up to 10% increased the sensory scores of the biscuits in terms of odor, flavor, and overall impression. PRACTICAL APPLICATION: The use of waste products in food industry is relevant in terms of the circular economy context. The enrichment of biscuit with waste fig seed powder could also supplies accessional channel for valorization of a food waste. Fig seed powder could be used to produce acceptable biscuits with improved nutritional quality.