Concentrations Of Volatile Compounds Research Articles

Production and Characterization of Red Fruit Spirits Made from Red Raspberries, Blueberries, and Strawberries

This study demonstrated the feasibility of fermenting and distilling low-commercial-value red fruits such as red raspberries, blueberries, and strawberries to produce high-value red fruit spirits. The fermentation process was efficient, with all red berry wines achieving a notable ethanol conversion yield (46.33 to 66.31%), without the need for nutrient supplementation or fruit juice solid separation, which showed no significant effect on the quality of the final product. Small-scale copper Charentais alembic distillation of the fermented red fruit juices resulted in fruit spirits equivalent to 1%, 7%, and 2% of the initial volume for red raspberries, blueberries, and strawberries, respectively. Except for the blueberry spirit, which had a lower volatile compound concentration (79.4 g/hL, absolute alcohol), all the produced red fruit spirits complied with legislation, including ethanol (37.9–40.2% v/v) and methanol (22.8–877.9 g/hL, absolute alcohol) concentrations and exhibited favorable aromatic profiles. The findings highlight that fermentation and distillation are straightforward, consistent, and reproducible methods, enabling the production of high-quality red fruit spirits from economically viable red fruit sources. This presents a significant opportunity in the spirits market, offering versatile applications as low-alcohol options, base spirits, or, with re-distillation, high-alcohol spirits.

Impact of different storage conditions with combined use of ethylene blocker on ‘Shalimar’ apple variety

This research investigates the impact of storage conditions on the quality and preservation of 'Shalimar' apples, a relatively new cultivar known for its resistance to apple scab and powdery mildew. The study explores the efficacy of different storage techniques such as regular atmosphere (RA), controlled atmosphere (CA), and dynamic controlled atmosphere with CO2 Monitoring (DCA-CD), as well as the integration of 1-methylcyclopropene (1-MCP) at different storage temperatures (1 °C and 3 °C). Various fruit quality parameters were monitored under different storage conditions, including firmness, titratable acidity, total soluble solids, background color, respiration, ethylene production, and volatile compounds. The results indicate that the controlled atmosphere (CA) at 1 °C emerges as an efficient method for long-term storage. However, it is noted that CA storage may impact the apple aroma, emphasizing the need for a balance between preservation and consumer acceptability. On the other hand, DCA-CD at variable temperatures (approximately 2.5 °C) offers a promising approach for maintaining fruit quality and a higher concentration of volatile compounds. Integrating 1-MCP enhances firmness, but its impact varies across storage conditions. Principal component analysis (PCA) provides insights into the relationships between storage conditions, fruit quality, and volatile compounds. This study contributes valuable insights into optimizing storage strategies for ‘Shalimar’ apples, addressing sustainability and quality preservation in apple production.

The Composition of Volatiles and the Role of Non-Traditional LOX on Target Metabolites in Virgin Olive Oil from Autochthonous Dalmatian Cultivars

The lipoxygenase pathway has a significant influence on the composition of the volatile components of virgin olive oil (VOO). In this work, the influence of the maturity index (MI) on the activity of the lipoxygenase enzyme (LOX) in the fruits of the autochthonous Dalmatian olive cultivars Oblica, Levantinka and Lastovka was studied. The analysis of the primary oxidation products of linoleic acid in the studied cultivars showed that LOX synthesises a mixture of 9- and 13-hydroperoxides of octadecenoic acid in a ratio of about 1:2, which makes it a non-traditional plant LOX. By processing the fruits of MI~3, we obtained VOOs with the highest concentration of desirable C6 volatile compounds among the cultivars studied. We confirmed a positive correlation between MI, the enzyme activity LOX and the concentration of hexyl acetate and hexanol in cultivars Oblica and Lastovka, while no positive correlation with hexanol was observed in the cultivar Levantinka. A significant negative correlation was found between total phenolic compounds in VOO and LOX enzyme activity, followed by an increase in the MI of fruits. This article contributes to the selection of the optimal harvest time for the production of VOOs with the desired aromatic properties and to the knowledge of the varietal characteristics of VOOs.

An insight into the association between volatile and other active components of sea buckthorn berries in barren soils of western China

Eight sea buckthorn samples growing in western China were comprehensively studied. The contents of terpenoids in Hippophae gyantsensis accounted for 24.83%. The volatile compound contents of Hippophae neurocarpa and Hippophae rhamnoides subsp. turkestanica reached more than 55 mg/kg. Furthermore, the lightly spiced refreshing scent of Hippophae neurocarpa was attributed to the presence of 1-octen-3-ol, isovaleraldehyde, 2-nonenal and styrene. And Hippophae gyantsensis had a fresher aroma due to its rich terpenoids, such as caryophyllene and humulene. These made it possible for them to be processed into essential oils. Similarly, Hippophae rhamnoides subsp. yunnanensis may be more suitable for the development and utilization of antioxidants due to its high level of polyphenols and flavonoids. And Hippophae rhamnoides subsp. turkestanica can be used to produce juice and fruit powder. The potential relationship between volatile and major nonvolatile compounds was preliminarily explored by partial least squares regression and the results indicated that fructose and glucose were mainly in connection with terpenoids. Polyphenols, flavonoids, malic acid and inositol may reduce the volatility of volatiles. Therefore, the volatile compound contents of Hippophae rhamnoides subsp. yunnanensis were less than 20 mg/kg.

A novel stepwise microwave hydrodistillation and extraction process for separating seed oil and essential oil simultaneously from perilla seeds

Stepwise microwave hydrodistillation and extraction (SMHDE) was utilized to separate perilla essential oil as a byproduct while boosting perilla seed oil yield and quality. The optimal process for producing perilla seed oil was determined by Plackett–Burman and Box–Behnken design experiments based on a factor screening experiment. Under ideal working conditions, the yield of seed oil was 36.49% ± 0.07%. The content of α-linolenic acid in perilla seed oil obtained by SMHDE was 69.90%, which was significantly greater than that obtained by Microwave-assisted method (MAE) (66.59%) and that obtained by Soxhlet extraction (SE) (66.51%). The yield of perilla seed essential oil obtained by SMHDE was 0.55 ± 0.14 mL/kg, and the main component was perillaldehyde, which was present at a concentration of 20.50%. GC‒MS analysis revealed that the content of volatile compounds in seed oil obtained by SMHDE (9.20%) was significantly lower than that obtained by MAE (10.94%) and SE (15.23%). Compared with traditional methods, SMHDE can effectively increase seed oil yield and quality without negatively influencing its fatty acid composition or physicochemical properties. These findings support the use of SMHDE to increase the production and quality of seed oil and prevent the waste of perilla essential oil resources.

Influence of seaweed dietary fibre as a potential alternative to phosphates on the quality profiles and flavour attributes of frankfurters

This study primarily aimed to investigate the influence of seaweed dietary fibre (SDF), as a potential alternative to phosphates, on the quality profiles and flavour attributes of frankfurters. The results revealed that SDF addition can significantly improve the cooking yield and texture characteristics of phosphate-free frankfurters (P < 0.05), and 1.00% SDF proved to be the optimal concentration for replacing phosphates in frankfurters. Moreover, electronic nose and electronic tongue analyses demonstrated that SDF incorporation potentially influences the aroma and taste of phosphate-free frankfurters. Furthermore, volatile compound analysis revealed that SDF addition potentially compensates for the decrease in volatile flavour compound content caused by phosphate deficiency. Generally, our results indicate that SDF can be successfully applied as a potential alternative to phosphates and subsequently improve the quality profiles and flavour attributes of phosphate-free frankfurters. Moreover, they provide valuable theoretical guidance for the processing of phosphate-free emulsified meat products.

Flavor profile and quality of strawberry wine are improved through sequential fermentation with indigenous non-Saccharomyces yeasts and Saccharomyces cerevisiae

In order to explore novel producing strategies for enhancing flavor compounds profile and quality of strawberry wine, we studied the effect of the sequential fermentation of two selected indigenous non-Saccharomyces yeasts (Hanseniaspora uvarum PGR9 and Kurtzmaniella quercitrusa PGT1) and Saccharomyces cerevisiae CGMCC 2.3854 on the fermentation kinetics, physicochemical characteristics, organic acids, antioxidant activity, volatile compositions, and sensory properties. Results showed that the ethanol content produced by the fermentation of Kq-Sc was significantly lower than that of Sc pure fermentation. In addition, the total volatile compounds concentration produced by the fermentation of Hu-Sc (16.2 ± 3.6 mg/L) and Kq-Sc (19.5 ± 3.1 mg/L) were significantly higher than that of Sc pure fermentation (13.8 ± 2.0 mg/L). In particular, the Kq-Sc strawberry wine presented the highest number of relative odor-active compounds (rOAV ≥1). Moreover, strawberry wine fermented by Hu+Kq-Sc showed the highest ABTS free radical scavenging ability and the highest overall sensory qualities. The results indicated that the K. quercitrusa PGT1 strain could be an alternative yeast for producing strawberry wine, and the sequential fermentations of Kq-Sc and Hu+Kq-Sc were effective strategies for improving the flavor and quality of strawberry wine.

Effect of osmotic dehydration combined with vacuum freeze-drying treatment on characteristic aroma components of peach slices

Hot air drying (HD), vacuum freeze drying (FD), and pilot-scale freeze drying (PSFD) are extensively used to prepare peach slices. However, the aroma of hot air drying and vacuum freeze-drying is yet to be addressed. In this study, HS-SPME-GC–MS was used to characterize and quantify the volatile compounds in peach slices. First, 33, 36, and 46 volatile compounds were identified and quantified in the HD, FD, and PSFD groups, respectively. PSFD is preferable to HD and FD in terms of the volatile compound types, content, and aroma profiles. PSFD was selected for subsequent permeation and dehydration experiments. The key aroma compounds with an OAV ≥ 1 were found in the PSFD30 group. GC-O analysis was conducted on the PSFD30 group, leading to the preliminary identification of 2-methylbutanal, pentanal, hexanal, 2-hexenal, phenylacetaldehyde, ethyl acetate, 2-methylbutyl acetate, ethyl lactate, linalool, methyl heptenone, and γ-octalactone as distinctive aromas in dried peach slices.

Влияние винных и виноградных спиртов на качество напитков из виноградного сырья

Table grapes that have lost their marketable appearance are considered waste products. However, such grapes still possess some technological properties that make it possible to use them as a raw material for wine and grape spirits. This research featured the effect of the composition and technology of table grape alcohols on the volatile compounds and sensory profile &#x0D; of grape beverages.&#x0D; The study involved six white and six red grape beverages. In the test samples, the fermentation process was stopped by adding wine spirits and grape spirits obtained by rectification of distillates from table grapes. In the control samples, the procedure involved rectified grain alcohol. The physicochemical parameters of drinks and spirits were defined by standard methods. The highly volatile compounds were determined by gas chromatography. The sensory assessment was conducted by panelists from the Winemaking Research Center of the North-Caucasian Federal Scientific Center of Horticulture, Viticulture, and Winemaking.&#x0D; In this study, the wine spirits and the grape spirits obtained from table grapes had no effect on the standard indicators, e.g., volatile acids and acetoin. However, they increased the mass concentrations of highly volatile compounds in the following manner: drinks with grain alcohol ˂ drinks with wine alcohol ˂ drinks with grape alcohol. The content of acetaldehyde increased by 10–14% while the contents of ethyl acetate, esters, and higher alcohols increased by 25–35, 4.5–8.5, and 15%, respectively. The furfural content increased by 0.4–1.4 mg/L in the samples with grape alcohol. The samples with white grape varieties acquired a more prominent floral-honey flavor whereas those with black grapes acquired hints of hazelnut and honey.&#x0D; As a result of the study, it was found that wine alcohol and grape alcohol moderately increased the content of volatile compounds in drinks and had a positive effect on their sensory perception, which proves the expediency of their use in beverage technology.

Quality and quantitative traits of non-alcoholic beer with flavour-improved taste

The non-alcoholic and low-alcohol beer market has grown significantly in recent years and is predicted to continue growing. However, non-alcoholic and low-alcohol beers have organoleptic problems and are not recognized by many consumers. The increasing popularity of alcohol-free beers (AFBs) fosters the industry's interest in delivering the best possible product. Yet, a remaining sensory issue of AFBs is the over-perception of wort flavor, caused by elevated concentrations of small volatile flavor compounds (i.e.aldehydes)still remains. Previously, molecular sieves (hydrophobic ZSM-5 type zeolites) were found as most suitable to remove these flavors by adsorption with high selectivity from the AFBs. In this work, a flavor-improved beer is produced at a pilot-scale using this novel technology, and its chemical composition, sensory profile, and stability are evaluated against a reference. Aldehyde concentrations in the flavor-improved product were found 79–93% lower than in the reference. The distinct difference was confirmed with a trained sensory panel and could be conserved even after three months of ageing at 30ºC. Future work will focus on the process design to scale up this technology. It is established that the release of a new kind of beer is economically profitable, since the expansion of the range contributes to a more complete use of production capacity, and consequently, reduced costs per unit of production, which ultimately leads to an increase in the profit of the enterprise.

Dynamic changes in metabolomics and flavoromics during industrial scale fermentation of Chinese traditional soy sauce

Flavor substances are crucial to the quality of soy sauce and closely related to the intermediate metabolites. This study systematically explored the dynamic changes in physicochemical characteristics, metabolomics and flavoromics during traditional Chinese soy sauce fermentation. The results indicated that the amino acid nitrogen gradually increased to 0.95 g/100 mL on the 13th day and then stabilized, and the changes of reducing sugars increased to 66.40 mg/mL on the 7th day and then slowly decreased. A total of 90 volatile compounds and 1172 non-volatile metabolites were detected. In the early fermentation period (1–7 day), alcohols, aldehydes and ketones were the main volatile compounds, but as fermentation proceeded, phenols and esters gradually accumulated. The total content of volatile compounds, mainly alcohols and phenols, reached the highest value on the 23rd day. Non-volatile metabolites were mainly amino acids, organic acids, lipids and carbohydrates, and the content and types of varied with fermentation time. KEGG analysis indicates there were significant changes in the proline and arginine metabolism in the middle and late periods (7–28 day) compared to the early fermentation period. Correlation analysis indicating a delicate balance between the transformation of metabolites and the formation of volatile compounds in traditional Chinese soy sauce.

Impact of Pure, Co-, and Sequential Fermentations with Hanseniaspora sp. and Saccharomyces cerevisiae on the Volatile Compounds of Ciders

Pure, co-, and sequential fermentations of Hanseniaspora uvarum, H. guilliermondii, and Saccharomyces cerevisiae strains were evaluated to improve the aromatic quality of ciders. In sequential fermentations, Hanseniaspora strains were used as starter, followed by S. cerevisiae inoculation succeeding one, two, and three days of fermentation. Kinetics, physicochemical parameters, and volatile compounds were assessed during 10 days of fermentation. The headspace technique was used to capture the volatile compounds from the ciders obtained in each experiment and analyzed by gas chromatography. Fermentations with pure strains of Hansenisaspora sp. showed a high population (&gt;1010 CFU/mL) but had a low fermentation rate (2.3–3.8 CO2 g/L/d), low consumption of amino acids (20–40 mg/L) with a high residual content, high sugar consumption (80–90 g/L), and low alcohol content (&lt;2.0% v/v). The H. uvarum strain produced a notably high ester content (245 mg/L). In the co-fermentations, H. guilliermondii with S. cerevisiae highlighted a significant production of higher alcohols, similar to that produced by S. cerevisiae alone (152–165 mg/L). In general, the maximum fermentation rate of the sequential inoculations was lower than co-fermentations but showed low residual nitrogen content (&lt;69 mg/L) and good conversion of sugars into ethanol (4.3–5.7% v/v). The highest concentrations of volatile compounds were observed in treatments involving the two non-conventional strains: H. uvarum with S. cerevisiae inoculation after three days (564 mg/L) and H. guilliermondii after just one day (531 mg/L) of fermentation. These differences stemmed from the metabolic activity of the strains. H. uvarum was influenced by the presence of Saccharomyces, whereas H. guilliermondii did not exhibit this effect. Thus, a pure H. uvarum inoculum has the potential to produce a demi-sec cider with low alcohol content and high content of esters, contributing to a fruity aroma. In addition, ciders with sequential inoculation were the most promising for dry cider processing concerning fermentation parameters and bioaroma enrichment.

Changes in volatile compounds in withering tea leaves after infestation with tea green leafhopper (Empoasca onukii Matsuda)

The effects of withering, cultivar yellowing, and Empoasca onukii infestation on tea leaf aroma have each been characterized, but variations in volatile compound (VC) contents as a result of co-occurrence of these factors remain unclear. In the present study, we analyzed VC contents in E. onukii-damaged leaves of Camellia sinensis (L.) cv. ‘Yinghong No. 9’ and the yellow bud variant ‘Yellowish Yinghong No. 9’ during the withering process. We found that glycoside-derived volatiles (GDVs) were the most abundant type of VCs, accounting for more than 83% of the total VC content. Linalool formed the main body of the tea aroma, contributing a floral, fruity scent. Differential accumulation of octanal and geranyl acetone in fresh leaves corresponded to differences in the aroma profiles between Yellowish Yinghong No. 9 and Yinghong No. 9. A higher degree of withering did not alter the pleasant aroma odors of Yellowish Yinghong No. 9, but rather maintained the floral, fruity flavors and reduced greenish odors and levels of defense-related compounds (e.g., benzeneacetaldehyde, benzyl nitrile) induced by E. onukii infestation. This study clearly establishes the effects of withering on the aroma profiles of E. onukii-infested leaves in both a standard and a yellow bud mutant tea variety, suggesting a method of maintaining the economic value of even insect-damaged tea leaves.

Monitoring of changes in the concentration of volatile organic compound in beef irradiated with accelerated electrons

The need to develop safe methods for radiation processing of food products to improve their quality and extend their shelf life stimulates new scientific research aimed at increasing their effectiveness. Oxidation of lipids and proteins occurred under the impact of ionizing radiation in products with a high fat and water content, such as chilled meat and fish products, leads to the formation of volatile organic compounds in the product thus giving it a specific smell and taste. During storage, biochemical processes associated with microbial enzymatic activity and auto-oxidation develop in processed refrigerated products. These processes also modify the volatile organic compounds, which affect the organoleptic properties of the product. The method of gas chromatography-mass spectrometry was used to study the behavior of volatile compounds identified in irradiated beef samples both immediately after irradiation and four days later to determine the effective dose range for the radiation processing of beef. Monitoring of the content of volatile compounds in beef samples irradiated by 1-MeV electrons within a dose range from 0.25 to 5 kGy showed that the content of certain alcohols, aldehydes, and alkanes exhibited pronounced dose- and time-dependent character. The developed mathematical model describes the dependence of the concentration of volatile compounds identified immediately after irradiation in beef samples on the irradiation dose. The model is based on the simultaneous occurrence of two competing processes: the decomposition of compounds due to their oxidation and accumulation due to oxidation of other compounds after exposure to ionizing radiation. The results obtained revealed that the effective dosage range of radiation treatment lies between 250 and 1000 Gy.

Aviation Mutagenesis Alters the Content of Volatile Compounds in Dahongpao (Camellia sinensis) Leaves and Improves Tea Quality.

Aviation mutagenesis is a fast and efficient breeding method. In this study, we analyzed the effect of aviation mutagenesis on volatile compounds and odor characteristics in Dahongpao fresh leaves and gross tea for the first time. The results showed that aviation mutagenesis significantly increased the total volatile compounds of Dahongpao fresh leaves and gross tea. Aviation mutagenesis most critically significantly increased the content of beta-myrcene in Dahongpao fresh leaves, prompting its conversion to beta-pinene, cubebol, beta-phellandrene, zingiberene, (Z,Z)-3,6-nonadienal, and 6-pentyloxan-2-one after processing, which in turn enhanced the fruity, green, spicy, and woody odor characteristics of the gross tea. This study provided a reference for further exploration of aviation mutagenic breeding of Camellia sinensis.

Effects of Bacillus amyloliquefaciens on volatile components and nutrient element contents of Mentha piperita L. grown under salt stress

Bacillus amyloliquefaciens (Ba) was applied to Mentha piperita L. (peppermint) seedlings grown at various salt levels (0, 50, 75, and 100 mM) for 42 days (six weeks). The study was conducted in a total of eight groups, with 24 seedlings per group. At the end of the study, the seedlings were analyzed for plant nutrient elements and volatile compound contents. The negative effect of salt was observed in almost all parameters. When all groups were evaluated for plant nutrient elements, Ba had a positive effect on Zn, Mn, Cu, and Na values compared to the control, but it did not show any effect on B, Fe, K, P, Mg, and Ca. In volatile compounds, limonene was detected as the major component in all groups. As a result of the evaluation based on limonene, the highest rate was found in the control, and the lowest rate was found in 100 mM NaCl. The salt-dependent inhibition between the groups with the highest and lowest limonene was 73%. While the negative effects of salt were observed in almost all parameters, the promoter effects of Ba were not as pronounced.

Comprehensive analysis of the effect of etiolated tea cultivars and harvest seasons on volatile compounds and in vitro antioxidant capacity in steamed green teas

To explore the effects of harvest seasons and etiolated cultivars on the volatile compounds of steamed green teas, this study analyzed comprehensively the volatile compounds of steamed green teas using simultaneous distillation extraction-gas chromatography–mass spectrometry (SDE-GC–MS) and chemometrics analytical techniques in combination with odor activity value (OAV). Additionally, the in vitro antioxidant capacity of the steamed green teas was evaluated. The results showed that 95 volatile compounds were identified, among which aldehydes, ketones, alcohols, and acids were the main types in steamed green teas made from etiolated tea cultivars. Furthermore, the relative content of volatile compounds in steamed green tea was significantly negatively correlated with season (P < 0.05). In steamed green teas harvested in different seasons, spring tea contained a higher abundance of volatile compounds such as (+)-δ-cadinene, farnesyl acetone, carvenone, trans-β-ionone, and nerolidol. The differences of total volatile compounds among the three etiolated tea cultivars were not remarkable (P > 0.05). Combined with the OAV, 20 and 19 key aroma compounds in steamed green teas from different harvest seasons and cultivars were identified, respectively, which could bring unique aromas to different steamed green tea samples. By comparison, summer tea had the strongest antioxidant capacity, while there was no obvious difference in the antioxidant capacity among cultivars. This study provided a scientific basis for the aroma quality of steamed green teas made from etiolated tea cultivars in different harvest seasons.

Characterization of the effect of non-Saccharomyces cerevisiaes on the non-volatile constituents and volatile profiles of low-alcoholic pomegranate beverages

To create the low-alcoholic beverages with excellent nutritional properties and flavor qualities, pomegranate juice was fermented with 16 strains of non-Saccharomyces yeasts from 9 species without added sugar. The effects of different yeasts on the non-volatile constituents (vitamins, organic acids, polyphenols), volatile compounds and sensory characteristics of the fermented beverages were comprehensively evaluated. The study revealed that non-Saccharomyces fermentations resulted in a higher abundance of polyphenols compared to the pomegranate juice and S. cerevisiae WLS21 (Sc21). The monomer phenols in Meyerozyma guilliermondii 12 (Mg12) were approximately twice the total of CK and 1.3 times of Sc21. Moreover, they led to a higher concentration of volatile compounds than the pomegranate juice. A total of 94 volatile compounds were identified in the pomegranate fermented beverages. In contrast to S. cerevisiae, Wickerhamomyces anomalus 1-1 and 10 (Wa1-1, Wa10), Pichia kudriavzevii 8 (Pk8) and Mg12 resulted in more acetate esters, and Zygosaccharomyces rouxii IFO 1130 and 53 (Zr1130, Zr53) yield higher levels of ethyl esters. A total of 40 volatiles with a relative odour activity value (rOAV) of ≥ 0.1 were identified, of which 14 were selected for principal component analysis (PCA). The sensory analysis confirmed that Zr1130, Zr53, Wa1-1, Wa10 and Pk8 strains exhibited superior aroma generation compared to Sc21. Furthermore, the partial least-squares regression (PLSR) analysis revealed that cherry, red fruits, black currant, citrus fruits, raspberry, black berry, pineapple, floral, sour and alcoholic odours had a significantly positive impact on the overall acceptability of the fermented beverages.

The different responses of Batocera horsfieldi adults to Juglans regia bark and leaf volatile compounds

AbstractBatocera horsfieldi (Hope) (Coleoptera: Cerambycidae) is an important pole borer pest. It causes serious harm to various hosts, particularly Juglans regia L. (Juglandaceae). In this study, headspace solid‐phase microextraction (HS‐SPME), gas chromatography–mass spectrometry (GC–MS), and electroantennogram (EAG) responses were combined to examine the mechanism by which B. horsfieldi adults locate their host, J. regia. The results showed that J. regia contained 65 volatile compounds in all, with 36 and 42 volatile substances in bark and leaves, respectively. Moreover, terpenes accounted for the largest relative content among the volatile compounds of bark and leaves, 43.4 and 78.9%, respectively. Ten of 19 selected volatile components elicited significant EAG responses in adult B. horsfieldi, which indicated that the pest may prefer certain volatile compounds when selecting a host. Sex and volatile concentration affected the responses of B. horsfieldi. Male adults had the strongest EAG responses to 1‐octen‐3‐ol, whereas female adults had the strongest EAG responses to linalool. Host selection in B. horsfieldi was somewhat positively associated with the concentrations of the effective volatile compounds in the host. Furthermore, B. horsfieldi showed varying preferences for isomers. This work provided data support for the development of insect attractants, and laid a theoretical foundation for the ecological protection of local forestry.

Effect of different pretreatments on the hydrolysis efficiency and flavor of squid viscera (Dosidicus gigas)

In order to better utilize the proteins in squid viscera (Dosidicus gigas), the effects of different pretreatments on the degree of hydrolysis (DH) and volatile compounds of hydrolysates were studied. The DH was used as an indicator to select alkaline protease as the optimal protease from 8 types of proteases. The hydrolysis conditions of alkaline protease and the flavor of the hydrolysates were investigated through single-factor, response surface methodology, and pretreatment-assisted hydrolysis experiments. The results showed that alkaline protease had the highest DH (42.08 ± 0.58%), with enzyme dosage of 1.5%, hydrolysis temperature of 45 °C, hydrolysis time of 5 h, and liquid-solid ratio of 4:1. The DH of the ultrasound group was significantly higher than other groups, with the highest DH (45.67 ± 0.34%) after ultrasound for 40 min (U40). The proportion of molecular weight < 1 kDa and the content of free amino acids (1613.64 mg/100 g) were the highest at U40. The electronic nose results indicated that the composition of organic sulfur and aliphatic compounds in U40 showed significant differences compared to other products. The U40 sample had the highest type and content of volatile compounds (especially benzaldehyde), which was more conducive to the volatilization of flavor substances. In conclusion, U40 pretreatment can effectively improve the DH and flavor of hydrolysates.