Lipid oxidation in baked products: Impact of formula and process on the generation of volatile compounds

Matrix-matched quantification of volatile organic compounds (VOCs) in gluten free flours and bakery products

The aim of this study deals with characterize the volatile profiles of gluten free flours and bakery products. An appropriate HS-SPME/GC-MS methods for the quantification analyses was performed and corn starch solid as standards was used. 34 different samples were analysed, and 127 compounds distributed in 4 classes (alcohols, aldehydes and ketones, heterocyclic compounds, and terpenes), that make up the aroma of these gluten free, were identified. The developed method is characterized by detection limits of 0.0004 and 0.0047 mg/kg for camphor and pyrazine, respectively, and linearity of quantification standards were between 0.990 and 0.998 for a range of 3-50 mg/kg.

Study on the effect of enzymolysis combined fermentation on reducing the off-flavor of egg white powder

BACKGROUND

The application of egg white powder (EWP) was subject to its off-flavor. In the present study, flavourzyme and lactic acid bacteria were used to treat egg white powder (EWP) and the mechanism effects of enzymolysis-fermentation were explored.

RESULTS

Compared with the control group, enzymolysis combined with fermentation treatment group (EW-EF) reduced the four-representative off-flavor compounds (geranyl acetone, 1-octen-3-ol, octanal and nonanal) by more than 62.66%. Fermentation produced esters with good flavor, and enzymolysis produced fresh amino acids. Characterization of protein structure indicated that fermentation decreased both fluorescence intensity and surface negative charges, accelerating the aggregation of proteins; enzymolysis promoted aggregation and degradation, improving the stability of the egg white proteins. Meanwhile, enzymolysis broke down the hydrophobic cavities bound to off-flavor compounds, releasing protein-bound off-flavor compounds and removing them through fermentation.

CONCLUSION

EW-EF had the best effect of off-flavor removal on EWP. The results of the present study could provide a green and effective method for improving the flavor of EWP. © 2024 Society of Chemical Industry.

Application of sourdough in gluten-free bakery products

ABSTRACTSIn recent years, the demand for gluten-free (GF) bakery products has grown rapidly due to the remarkable rising number of celiac patients and the increasing health awareness of GF products. However, GF products generally suffer from defects such as poor sensorial level, low nutritional value, high prices and short shelf life. Sourdough is the important starter culture applied in bakery field, and it has been proven to be ideal for enhancing the overall quality of bakery products. This review aims to systematically reviewed the application of sourdough in GF bakery products and its improvement to GF bakery products in terms of texture, shelf life, nutrition and flavor. Its positive effects derive from the complex metabolic activities of sourdough microorganisms, such as acidification, proteolysis, production of exopolysaccharides (EPS), activation of endogenous enzymes, and production of antibacterial substances. Finally, researchers are encouraged to expand the use of sourdough in GF bakery products to increase the variety of GF products. And the technical and nutritional potential of sourdough should be developed more widely.

Comparison of Storage-Related Volatile Profiles and Sensory Properties of Cookies Containing Xylitol or Sucrose

Excessive consumption of simple sugars is responsible for non-communicable diseases such as obesity, cardiovascular diseases, and diabetes. Xylitol has anticarcinogenic, prebiotic-like characteristics and a lower glycaemic index and caloric value than sugars, which makes it a valuable alternative sweetener. The aim of this study was to examine the effects of storage of volatile compounds and sensory profiles of cookies containing xylitol as a sucrose alternative or sucrose by applying solid-phase microextraction gas chromatography/mass spectrometry and quantitative descriptive analysis. The volatile compound profiles of both kinds of cookies were similar, especially regarding markers of Maillard reactions (Strecker aldehydes, pyrazines) and unfavourable compounds (aldehydes, hydrocarbons, and organic acids). Throughout the period of storage lasting 0-9 months, the total content of hydrocarbons was stable and averaged 10.2% in xylitol cookies and 12.8% in sucrose cookies; their storage for 12 months significantly (p < 0.05) increased the contents to 58.2% and 60.35%, respectively. Unlike sucrose, xylitol improved the stability of the pH and water activity of cookies and sensory attributes such as buttery aroma and texture characteristics during 12 months of storage. The results indicated that 9 months of cookie storage was the maximum recommended period. The inclusion of xylitol in cookies might replace sucrose and high-fructose-corn syrup and synthetic additives commonly used in industrial production.

Quality and Nutritional Changes of Traditional Cupcakes in the Processing and Storage as a Result of Sunflower Oil Replacements with Refined Olive Pomace Oil

Recent nutritional studies have shown that the regular consumption of olive pomace oil (OPO) contributes to cardiovascular and cardiometabolic disease prevention. OPO could be a healthier alternative to the polyunsaturated oils employed in a number of bakery foods. However, little is known about the quality and nutritional changes of OPO in these products, especially the amounts of its bioactive components that finally reach consumers. The aim of this research was to evaluate refined OPO as a substitute for sunflower oil (SO) in cupcakes specially manufactured with a 6-month shelf-life. The influence of processing and storage on lipid oxidative changes and the levels of OPO bioactive components was studied. OPO samples exhibited much higher resistance to oxidative degradation in the processing and especially after storage, which had a greater oxidative impact. OPO reduced considerably the levels of oxidised lipids. HPLC analysis showed hydroperoxide triglyceride concentrations of 0.25 (±0.03) mmol/kg fat against 10.90 (±0.7) mmol/kg in the control containing SO. Sterols, triterpenic alcohols and triterpenic acids remained unchanged, and only slight losses of squalene (8 wt%) and α-tocopherol (13 wt%) were observed in OPO after processing and storage, respectively. Therefore, OPO preserved its nutritional properties and improved the quality and nutritional value of the cupcakes.

Effects of egg powder on the structure of highland barley dough and the quality of highland barley bread

The influences of egg white (EW), egg yolk (EY) and whole egg (WE) on the structure of highland barley dough and the quality of highland barley bread were explored. The results showed that egg powder reduced G' and G" of highland barley dough, which led to the softer texture of dough and endowed bread with a larger specific volume. EW increased the percentage of β-sheet of highland barley dough, EY and WE promoted the transformation from random coil to β-sheet and α-helix. Meanwhile, more disulfide bonds were formed from free sulfhydryl groups in the doughs with EY and WE. These properties of highland barley dough could help highland barley bread develop a preferable appearance and textural feature. It is worth noting that highland barley bread containing EY has more flavorful substances and a better crumb structure, which were similar to that of whole wheat bread. The highland barley bread with EY received a high score according to the sensory evaluation in consumer acceptance.

Characterization of physical properties, volatile compounds and aroma profiles of different salted egg yolk lipids

Salted egg yolks (SEY) have a desirable and unique flavor with multiple underlying applications in food processing, and their abundant lipids contribute to a creamy and pleasant aroma. However, it is important to maintain the stability of the SEY flavor, which depends to a large extent on the egg species and the processing method. This study aimed to extract different SEY lipids with conventional solvents, analyze the fatty acid composition, and screen the volatile compounds to elucidate the flavor differences between salted hen eggs and duck eggs. Compared to ethanol extraction, acetone-extracted lipids had lower acid value and viscosity, and almost had no phospholipid content. Fatty acid analysis revealed that the highest content of fatty acid in SEY lipids was oleic acid, followed by palmitic acid and linoleic acid, while there were significant variations of different SEY lipids in the fatty acid profiles. The volatile compounds were identified by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and the overall odor was detected by the electronic nose (E-nose). A total of 27 volatile compounds were analyzed in SEY lipids and divided into 8 chemical classes. The aldehydes, furans and pyrazines were decreased, and the hydrocarbons were increased compared with untreated SEY. The combination of the physical properties and flavor evaluation of SEY lipids could provide a theoretical basis for the extension of the characteristic flavor matrix in SEY.

Effect of Alkali on the Microbial Community and Aroma Profile of Chinese Steamed Bread Prepared with Chinese Traditional Starter

Alkali is an indispensable additive in Chinese steamed bread (CSB) production. This work aimed to evaluate the key roles of alkali in the microbial community of dough fermented using Chinese traditional starter (CTS) and the aroma profiles of CSB. The dominant fungi in CTS and fermented dough were members of the phylum Ascomycota and the genus Saccharomyces. Pediococcus, Companilactobacillus, and Weissella were the dominant bacterial genera in CTS and fermented dough. Adding alkali could retain the types of dominant yeasts and LAB derived from CTS, decrease the relative abundance of Companilactobacillus crustorum and Weissella cibaria, and increase that of Pediococcus pentosaceus, in fermented dough. Principal component analysis (PCA) indicated that adding alkali decreased the content of sourness-related volatiles in CSB fermented by CTS. Correlation analysis showed that Pediococcus and Weissella in fermented dough were positively correlated with the lipid oxidation flavor-related compounds in CSB, and Lactobacillus was positively correlated with sourness-related aroma compounds. Synthetic microbial community experiments indicated that CSB fermented by the starter containing P. pentosaceus possessed a strong aroma, and adding alkali weakened the flavor intensity. Alkali addition could promote the formation of ethyl acetate and methyl acetate with a pleasant fruity aroma in W. cibaria-associated CSB.

Chemical Properties of Peanut Oil from Arachis hypogaea L. 'Tainan 14' and Its Oxidized Volatile Formation

Arachis hypogaea L. ‘Tainan 14’ has purple skin characteristics. This study investigated the effects of different materials (shelled or unshelled peanuts) and temperatures (120 or 140 °C) on the properties of extracted peanut oil. The results show that its antioxidant components (total flavonoid, α−tocopherol, and γ-tocopherol) and oxidative stability were mainly affected by the roasting temperature (p < 0.05). Fifty-eight volatile compounds were identified by peanut oil oxidation and divided into three main groups during the roasting process using principal component analysis. The volatile formation changes of different materials and temperatures were assessed by agglomerative hierarchical clustering analysis. These results provide useful reference information for peanut oil applications in the food industry.

Saponins from Pea Ingredients to Innovative Sponge Cakes and Their Association with Perceived Bitterness

Pea-based ingredients are increasingly being used in foods because of their nutritional, functional and environmental benefits. However, their bitter taste is not appreciated by consumers. Saponins have been reported to be bitter in whole pea flour (PF) but not in the purified ingredients obtained from it, such as pea protein isolate (PPI) and pea starch (PS). In addition, the evolution of saponins in cooked foods made from these ingredients and their relationship to bitter flavor has not been investigated. This study, therefore, explored the presence of two bitter saponins, βg and Bb, in whole pea flour (PF) and a composite flour reconstructed from the two main fractions (PS + PPI). In addition, it investigated the impact of baking on the chemical state of these compounds in a sponge cake. Finally, the sensory impact of the baking process on the perceived bitterness of cakes made with these two pea flours was also evaluated. High-Performance Liquid Chromatography–High-Resolution Mass Spectrometry (HPLC-HRMS) was used to identify and quantify pea saponins in the flours and cakes, and a descriptive sensory analysis was obtained by a trained panel to assess sensory differences in bitterness. Our results showed marked differences in saponin concentration and composition among the pea ingredients studied. Concentrations were highest in PPI (1.497 mg·g⁻¹ dry matter), with 98% of saponin Bb. PS had the lowest saponin concentration (0.039 mg·g⁻¹ dry matter, with 83% Bb), while 0.988 mg·g⁻¹ dry matter was quantified in PF, with only 20% Bb and 80% βg. This research also highlighted the thermal degradation of saponin βg to Bb in sponge cakes during baking at 170 °C. However, at a sensory level, these chemical changes were insufficient for the impact on bitterness to be perceived in cakes made with pea flour. Moreover, baking time significantly reduced the bitter flavor in cakes made with the composite flour (PS + PPI).

Applicability of pea ingredients in baked products: Links between formulation, reactivity potential and physicochemical properties

This study aimed to evaluate the applicability of purified pea ingredients (starch and protein isolate) by assessing their potential to form volatile compounds during the different steps of sponge cake development compared to pea flour and wheat flour. While pea flour was highly susceptible to lipid oxidation during batter beating, the combination of purified pea starch and pea protein yielded significantly fewer oxidation markers with known green-beany off-odors. This was due more to the inactivation of lipoxygenase during flour fractionation than to differences in batter structure. However, fractionated ingredients were highly prone to participating in the Maillard reaction and caramelization during baking, leading to a more complex mixture of pyrazines, Strecker aldehydes and furanic compounds with potential malty and roasted notes compared to cakes based on pea flour or wheat flour. These findings confirm that using purified pea fractions can create high-quality products with an attractive composition.

The study of microbial diversity and volatile compounds in Tartary buckwheat sourdoughs

Microorganisms play an essential role in forming volatile compounds in traditional staple products. Tartary buckwheat, as a medicinal and food material, has high nutritional value but its development and utilization are seriously restricted due to its poor flavor. In this study, 16S rRNA and ITS rRNA sequencing were used to analyze the microbial diversity of Tartary buckwheat sourdoughs, while HS-SPME-GC/MS was used to identify volatile compounds during fermentation. The results showed that Lactococcus and Weissella were the dominant bacterial genus. Wickerhamomyces, Penicillium, and Aspergillus were the main fungal genera in the Tartary buckwheat sourdoughs. And the main volatile compounds in Tartary buckwheat sourdough were pyrazine compounds. After 12 h of fermentation, a large amount of alcohol and esters were produced, which endowed the sourdough with a good flavor. This suggests that sourdough fermentation could significantly improve the flavor of Tartary buckwheat.

Sensory attributes, dog preference ranking, and oxidation rate evaluation of sorghum-based baked treats supplemented with soluble animal proteins

Treats are offered to dogs to reinforce the animal-owner bond and as rewards. Wheat, which contains gluten (gliadin and glutenin proteins), is often used in treats. The US is a leading producer of sorghum which might be an alternative; however, it does not have functional properties to form viscoelastic doughs, because is mainly composed of kafirin protein. Therefore, the objectives of this study were to determine the effects of supplementing soluble animal proteins in whole sorghum rotary molded baked dog treats on dog preference, sensory attributes, and oxidation rate. The treats were produced in triplicate in a 2x4 + 1 augmented factorial arrangement of treatments. Two whole sorghum flours (WWS and WRS), four protein sources [none (NC), spray-dried plasma (SDP), egg protein (EP), and gelatin (GL)], and a positive control with wheat (WWF-GTN) were evaluated. A preference ranking test with twelve dogs was performed. Additionally, five trained panelists scored the intensity of appearance, aroma, flavor, texture/mouthfeel, and aftertaste attributes. Finally, the treats were stored at 30°C and 60% RH, and hexanal concentrations were measured on days 0, 28, 56, and 112. The data was analyzed using the statistical software SAS for the animal and oxidation rate evaluations with significance considered at P<0.05. The descriptive sensory evaluation data was analyzed using multivariate analysis (XLSTAT). The dogs did not detect differences among WWF-GTN, WWS, or WRS treats when evaluated together. However, the WWF-GTN, WWS-SDP and WWS-EP treatments were preferred among the white sorghum treatments. The EP treatments led to some consumption difficulties by dogs because of their hard texture. The panelists reported a high degree of variation in the appearance and texture across treatments. The WRS and WWS treats with SDP or EP were darker, while NC treats had more surface cracks. Initial crispness, hardness, and fracturability were higher in EP treatments compared to all other sorghum treatments. The predominant flavor and aftertaste identified were "grainy." The hexanal values for all treats were <1.0 mg/kg except for the EP treatments that had higher values (2.0-19.3 mg/kg) across the shelf-life test. This work indicated that the replacement of WWF-GTN by WWS and WRS, along with soluble animal proteins like SDP or GL would produce comparable preference by dogs, oxidation rates, product aromatics, flavor, aftertaste attributes, and, at a lower degree, product texture.

Variation of Volatile Compounds and Corresponding Aroma Profiles in Chinese Steamed Bread by Various Yeast Species Fermented at Different Times

To control the fermentation process of yeast-Chinese steamed bread (CSB), the volatile compounds and odor profiles of yeast-CSBs during fermentation were comprehensively investigated by sensory evaluation, gas chromatography-mass spectrometry, gas chromatography-olfactometry (GC-O), and odor activity value (OAV). Eight sensory attributes were established, and quantitative descriptive analysis results showed that CF1303-CSB had intense sweet and sweet aftertaste attributes, CF1318-CSB was characterized by milky, wheaty, and yeasty attributes, while CL10138-CSB presented distinct sour, winy, and floury attributes. A total of 41 key aroma-active compounds were detected, and phenylethyl alcohol was the most potent aroma compound with a flavor dilution (FD) of 1024. CF1303-CSB, CF1318-CSB, and CL10138-CSB contained 24, 22, and 21 key aroma compounds, respectively, based on the OAV. These key aroma compounds can be used as the potential markers to monitor the yeast-CSBs during the fermentation process. Five compounds, including β-myrcene, 2-phenoxyethanol, methyl cinnamate, guaiacol, and o-cresol, were first identified in CSB. These results provide theoretical basis for processing and quality control of yeast-CSBs.

From flours to cakes: Reactivity potential of pulse ingredients to generate volatile compounds impacting the quality of processed foods

This study investigated the impact of substituting wheat with pulse flours (lentil, chickpea, lupin, green and yellow pea) on reactivity during different steps of sponge cake development. Pulses exhibited a greater ability to generate volatiles with probable odor activity. Batter beating initiated lipid oxidation which depended on lipoxygenase activity and the fatty acid profile of the flours. Among the pulses, pea batters were richest in oxidation markers whereas lupin was least reactive, probably due to thermal pre-treatment. Baking triggered caramelization and Maillard reactions, notably with the pulse products which were particularly enriched in pyrazines and furanic compounds. Principle component analysis revealed that pea cakes were associated with oxidation markers that typically possess green-beany flavors, while Maillard markers known to impart nutty, roasted notes were assigned to lentil and chickpea cakes. These findings highlight the importance of ingredient type and its pre-processing in the development of quality-related markers for gluten-free products.

Sugars Replacement as a Strategy to Control the Formation of α-Dicarbonyl and Furanic Compounds during Cookie Processing

In the last decade, several preventive strategies were considered to mitigate the chemical hazard accumulation in food products. This work aimed to study the effect of different sugars on the development of the main chemical hazard in cookies. For this purpose, model biscuits prepared using sucrose, fructose, and glucose were baked at different temperatures (150, 170, and 190 °C) and for different times (from 5 to 45 min), and the levels of α-dicarbonyl compounds, such as 3-deoxyglucosone (3-DG), glyoxal (GO) and methylglyoxal (MGO), 5-hydroxymethylfurfural (HMF), and furanic aromatic compounds were monitored. The replacement of sucrose in the cookie recipes with monosaccharides had as a consequence the highest accumulation of 3-DG (200-600 times higher), MGO, HMF, and furanic volatile compounds, while the use of sucrose allowed for maintaining the 3-DG, MGO, and HMF levels at less than 10 mg/kg dry matter in cookies for the estimated optimal baking time. Moreover, cookies with sucrose were characterised in terms of volatile compounds, mainly in terms of lipid oxidation products, while cookies with fructose or glucose baked at the highest temperature were characterised almost exclusively by Maillard reaction products, confirming a faster development of this reaction during baking at the studied temperatures.

Effect of processing and storage on the volatile profile of sugarcane honey: A four-year study

Sugarcane honey (SCH) is a syrup from Madeira Island recognized by its unique and excellent aroma, associated to volatile organic compounds (VOCs) generated during the well-defined five stages of its traditional making process. The establishment of volatile profile throughout all SCH-making stages during four years, allowed the evaluation of the influence of each stage in the typical characterisitcs of SCH. One hundred eighthy seven VOCs were identified, being associated to several origins and formation pathways. VOCs formed during stage 1 and 2 were originate from raw material, and its oxidation (i.e. enzymatic browning) and thermal degradation (i.e. lipid oxidation, Maillard reactions, Strecker degradation). In stage 3 and 4, the caramelization and melanoidin degradation also occurred, while in stage 5, the thermal degradation continues, followed by microbial activity. Chemometric analysis allowed to identify 35 VOCs as potential markers for processing control by the producers and as guarantee of the typicality and authenticity of SCH. Based on the obtained results, we propose for the first time an innovative schematic diagram explaining the potential reactions and pathways for VOCs formation during the different steps of the SCH production.

Effect of Different Egg Products on Lipid Oxidation of Biscuits

Egg products are one of the main ingredients used in bakery industries, and they contain cholesterol. Cholesterol suffers several chemical changes during the food processes, allowing some potentially toxic compounds called cholesterol oxidized products (COPs). Thus, the aim of this work was to study the evolution of lipid oxidation from eggs to egg products, and to evaluate the influence of egg products on COPs formation in biscuits formulated with them. The results confirmed that spray-drying technology improves the cholesterol oxidation 2.6 times compared to pasteurized eggs. Biscuit samples showed a COPs content that is strictly related to the egg products used. Samples formulated with spray-dried eggs noticed lower amounts of COPs compared to those formulated with pasteurized eggs. It is important to stress that COPs composition was different between the two samples, underlining that the kinetic of COPs formation is dependent on the type of egg products.

Characterising the sensory quality and volatile aroma profile of clean-label sucrose reduced sponge cakes

The sensory and aroma quality of 30% (w/w) sucrose reduced sponge cakes incorporating clean-label replacers were investigated. The sensory quality of the reformulated sponge cakes varied, with those containing apple pomace powder (APP) showing the greatest difference to the control (SC100). Volatile profiles mainly differed in relation to compounds derived from the Maillard reaction, caramelisation and lipid oxidation. Thrity six aroma active volatile compounds were identified in the SC100, APP and oligofructose (OLIGO) sponge cakes by olfactometry. Furfural 'spicy bready' contributed most to the overall aroma of all samples, with factor dilution values differing the most for heptanal 'fatty cake crust', methional 'potato damp', and 2,5-dimethylpyrazine 'cake crust, nutty'. This study provides an in-depth insight into the impact of sugar reduction reformulation on the sensory perception of sponge cakes and demonstrates how this approach can be used to improve the sensory perception of reduced sucrose sponge cakes.

Characterization of salted egg yolk flavoring prepared by enzyme hydrolysis and microwave irradiation

The salted egg yolk (SEY) is very popular in China for its pleasant flavor and texture. However, the long production cycle of traditional pickling and the waste of salted egg white had limited its industrialization. To solve these problems, a salted egg yolk flavoring was generated through enzymatic hydrolysis and microwave irradiation from fresh egg yolk in this study. The combination of enzymatic hydrolysis and microwave irradiation could force water and lipids in egg yolk to migrate out, and lead to lipid oxidation in high temperature. Lipid oxidation and Strecker degradation were defined as the major pathways of flavor generation. Among the generated volatile compounds, Hexanal, Heptanal, Benzaldehyde and 2-Pentyl-furan were supposed closely related to SEY flavor. This method could be used as an alternative method for the production of salted egg yolk. Furthermore, it could provide a foundation for further investigation of egg yolk containing flavor system.

Modeling the Effect of the Oxidation Status of the Ingredient Oil on Stability and Shelf Life of Low-Moisture Bakery Products: The Case Study of Crackers

In packed low-moisture foods such as crackers, oxidation is generally the main cause of quality depletion during storage. It is commonly believed, but scarcely investigated, that product shelf life depends on the oxidative status of the lipid ingredients. In this study, the influence of oxidation degree of the ingredient sunflower oil on cracker oxidative stability and hence shelf life was investigated. To this aim, oil with increasing peroxide values (PVs) (5, 11, and 25 mEqO₂/kg_oil) was used to prepare crackers. Just after production, crackers presented similar peroxide and rancid odor intensity, probably due to the interactive pathways of oxidative and Maillard reactions. Crackers were packed and analyzed for PV and rancid odor during storage at 20, 40, and 60 °C. Rancid odor well discriminated cracker oxidative status. Relevant oxidation rates were used to develop a shelf life predictive model based on the peroxide value of the ingredient oil. It was estimated that an oil PV from 5 to 15 mEqO₂/kg_oil shortens cracker Shelf Life (SL) by 50%, independently of storage temperature. These results demonstrate the critical impact of ingredient quality on product performance on the market.

Yeast-Free Doughs by Zymomonas mobilis: Evaluation of Technological and Fermentation Performances by Using a Metabolomic Approach

This research focuses on the leavening performances and development of volatile compounds of three strains of Zymomonas mobilis in the production of yeast-free doughs. Z. mobilis DSM 3580, 424, and 473 were used in doughs supplemented with glucose and with or without NaCl. Z. mobilis produced about 10 mg ethanol/g dough, with maximum dough volumes (640–680 mL) being reached after 2 h leavening. NaCl addition postponed this parameter up to 6 h. Among organic acids, hexanoic acid resulted the highest produced compound; DSM 424 and 473 formed more propanoic, butanoic and pentanoic acid, being both negatively affected by NaCl. Esters were mainly discriminated on NaCl addition, with octanoic acid (DSM 3580), butanoic acid (DSM 424), and propanoic acid (DSM 473) ethyl esters as main components. DSM 3580 specifically produced 2-heptanal, DSM 424 2-hexadecenal, (E) and DSM 473 octanal, while DSM 424 and DSM 473 produced 2-butanone-4-hydroxy better than DSM 3580. Z. mobilis unique signatures were the production of nonanoic and undecanoic acids, 2-hexadecenal, (E), L(+)-tartaric acid diethyl ester and 3-decen-5-one, 4-methyl, (E). This outcome can pave the way for using Z. mobilis in baking goods, providing innovation possibilities in the area of yeast-free leavened products.

Fatty Acids, Volatile and Sensory Profile of Multigrain Biscuits Enriched with Spent Malt Rootles

Spent malt rootlets, a by-product of the brewing industry, are a rich source of protein, essential amino acids, healthy fats, polyphenols and minerals, and could be a new promising type of raw material from the nutritional, economic, sensory, and technical perspectives. However, their specific aroma profile could limit their addition in baked products. The aim of this work was to study the effect of spent malt rootlets addition on volatile derivatives of enriched biscuits in relation to their sensory profile. For this purpose, spent malt rootlets and enriched biscuits (0-25% spent malt rootlets added) were analyzed by GC-MS techniques, in order to obtain their fatty acids methyl esters and volatile compounds profile, while for the sensory analysis a nine-point hedonic score test was used. The results of this study reveal the fatty acids and volatile profile of spent malt rootlets and of the enriched biscuits with spent malt rootlets pointing out the contribution of fatty acids to the generation of aroma compounds. The influence of different aroma compounds on the consumer's preferences was studied and the optimum level addition of spent malt rootlets in multigrain biscuits was found to be 15%.

Analysis of Volatile Compounds from Wheat Flour in the Heating Process

Volatile profiling was carried out during heating through vacuum-assisted headspace solid-phase microextraction combined with gas chromatography-mass spectrometry to better understand the flavor forming mechanism of flour products. Ninety-two volatile compounds were detected and identified, including aldehydes (25), ketones (15), alcohols (9), nitrogen- and sulfur-containing compounds (6), benzene derivatives (15), furans (10), and acids and esters (12). The formation temperature of each volatile was also determined. Results showed that temperature played an important role in the formation and content of volatile compounds. In the low-temperature range (60 °C–100 °C), the flavor composition of flour was mainly composed of C6–C10 volatile aldehydes and alcohols. At temperatures exceeding 100 °C, especially at 120 °C, many long carbon chain aldehydes and alcohols, furans, acids, esters, nitrogen- and sulfur-containing compounds were formed. The formation rate of most identified volatile compounds increased during heating, especially from 90 °C to 130 °C.

Characterization of key aroma-active compounds in four commercial egg flavor Sachimas with differing egg content

To characterize the aroma components of Sachima and provide insight into the influence of egg on the flavor of Sachima, the key aroma-active compounds in four commercial egg flavor Sachimas with different egg content, which named Premium, Classical, Whole egg, and Egg yolk, were identified using GC-MS-O analysis, aroma extract dilution analysis (AEDA) combined with sensory evaluation. In total, 75 volatile compounds were identified by GC-MS, including 26 compounds were revealed of having aroma activities by AEDA/GC-O. The major volatile compounds in Sachima were the aldehydes and heterocyclic compounds. The OAV further revealed the significant activity of eight key aroma-active compounds include 2-methylbutanal, 3-methylbutanal, hexanal, n-propylacetate, 2-pentylfuran, 2-ethylpyrazine, nonanal, and benzaldehyde. The OAV of 2-methylbutanal and 3-methylbutanal were much higher in Premium sample that has the most egg content, than that in other samples, whereas hexanal was the highest in Whole egg samples. The plot analyzed by PLS suggest that the Premium sample with more egg content was shown more complicated flavor than other kind of Sachima. Practical applications Sachima is a type of famous sweet Chinese traditional pastries. The flavor and texture of this kind of pastry were appreciated by all age group, especially for almost all elderly Chinese. Because Sachima is not only a suitable food that easy to chew, but a type of food which filled with childhood memory. Egg flavor of Sachima was always the most popular and classic flavor category. However, the characteristic aroma compounds of Sachima-one of the most important factor of the Sachima's quality-have been still uncovered and had not been identified yet, not to mentioned the comparison between different egg content in Sachima. What's more, GC-MS-O/AEDA analysis has been always a very effect and well-known method for aroma compounds analysis. This study trying to find the contribution of eggs to Sachima and the key aroma-active compounds of Sachima, so as to provide some useful information for practical production and flavor quality improving.

Chemical-nutritional parameters and volatile profile of eggs and cakes made with eggs from ISA Warren laying hens fed with a dietary supplementation of extruded linseed

Objective

The aim of this study was to evaluate the chemical-nutritional parameters, oxidative stability and volatile profile of eggs and cakes made with eggs from laying hens fed with a dietary supplementation of extruded linseed.

Methods

Two thousand ISA Warren laying hens were randomly divided into two groups: a control group was fed with a standard diet while the experimental group received the same diet supplemented with 7% of extruded linseed. The trial lasted 84 days, in which three samplings of laid eggs were performed. Samples of eggs and food systems arising from eggs were then analyzed in order to obtain information about β-carotene and total flavonoid content, antioxidant activity, fatty acid profile, lipid oxidation, and volatile profile.

Results

Linseed induced the increase of α-linolenic acid with consequent reduction of the ω-6/ω-3 ratio (4.3:1 in egg yolk); in addition to this, was evidenced the cholesterol reduction and the significant increase in total flavonoids and β-carotene, although no variations were detected in antioxidant capacity. Even in cooked products there was not only a direct effect of linseed in increasing α-linolenic acid, but also in inducing the reduction of cholesterol and its major oxidation product, 7-ketocholesterol. The dietary linseed integration was also shown to affect the volatile profile of baked products.

Conclusion

Data confirmed that dietary supplementation with extruded linseed resulted in food products with interesting implications for human health. With regard to the volatile profile of baked products it would be necessary undertake further sensorial analysis in order to evaluate any variations on flavor and consumer acceptability.

Preparation of N-(1-Deoxy-Α-D-Xylulos-1-Yl)-Glutamic Acid via Aqueous Maillard Reaction Coupled with Vacuum Dehydration and Its Flavor Formation Through Thermal Treatment of Baking Process

Amadori rearrangement product (ARP) derived from glutamic acid (Glu) and xylose (Xyl) was prepared by aqueous Maillard reaction. Subsequently, ion exchange chromatography, MS, and NMR were used for purification and identification, confirming that the molecular formula of ARP was C₁₀ H₁₇ NO₈ , namely N-(1-deoxy-α-D-xylulos-1-yl)-glutamic acid, with a molecular mass of 279 Da. To improve the aqueous yield of ARP, a thermal reaction coupled with vacuum dehydration was used and the yield of ARP was increased from 2.07% to 75.11%. Furthermore, flavor formation capacity of ARP by a thermal treatment simulated to a baking process was compared with Maillard reaction products, Maillard-dehydration reaction products, and Glu-Xyl mixture. The results indicated that a larger amount of volatile flavor compounds and a biscuit-like, burnt aroma was generated rapidly from the mixture of ARP and unreacted Glu-Xyl, which could be a potential flavor enhancer for baked foods. PRACTICAL APPLICATION: Maillard reaction performed in aqueous medium through thermal reaction combined with vacuum dehydration is a novel and practical technology that could be widely used to produce Maillard reaction intermediates (MRIs), such as Amadori or Heyns rearrangement products, which are regarded as significant nonvolatile aroma precursors and have stable physical and chemical properties compared with Maillard reaction products (MRPs). MRI derived from glutamic acid and xylose is a potential substitute of MRPs for flavorings preparation and shows a great capacity to generate fresh flavors in a short time at high temperature, which meets the requirements of baking foods. Therefore, the new developed method could be a promising tool for MRI preparation and application in food and flavoring industries.

Determination of Antioxidant Capacity, Phenolics and Volatile Maillard Reaction Products in Rye-Buckwheat Biscuits Supplemented with 3β-d-Rutinoside

The Maillard reaction (MR) is responsible for the development of color, taste and aroma in bakery products though the formation of numerous aroma compounds such as pyrazines, pyrroles and aldehydes, nonvolatile taste active compounds and melanoidins. In this article, we investigate the effect of quercetin 3β-D-rutinoside (rutin) supplementation, at the level of 5⁻50 mg per 100 g, of rye-buckwheat biscuits on the formation of phenolics and volatile Maillard reaction products (MRPs) such as pyrazines, furfuryl alcohol and furfural, determined by headspace solid phase microextraction followed by gas chromatography⁻mass spectrometry (HS-SPME/GC⁻MS), in addition to the effect on the antioxidant capacity. The study confirmed that rutin was stable under baking conditions as showed by its content in rye-buckwheat biscuits. Supplementation of biscuits with increasing amounts of rutin resulted in the progressive increase of total phenolics and antioxidant capacity measured by DPPH and OxHLIA assays, but it had no effect on their sensory quality. From the eighteen compounds identified by HS-SPME/GC⁻MS in the volatile fraction of biscuits were quantitated as a compounds-of-interest: methylpyrazine, ethylpyrazine, 2,3-; 2,5- and 2,6-dimethylpyrazines, as well as furfural, furfuryl alcohol and hexanal. The rutin supplementation of biscuits might be one of the factors to influence the formation of both desirable volatile compounds and undesirable toxic compounds. In conclusion, this study indicates for the significant role of polyphenols on the formation of volatile compounds in biscuits with possible future application in the development of healthy bakery products with high antioxidant capacity.

Identification of Key Aroma Compounds in Type I Sourdough-Based Chinese Steamed Bread: Application of Untargeted Metabolomics Analysisp

Untargeted metabolomics is a valuable tool to analyze metabolite profiles or aroma fingerprints of different food products. However, less attention has been paid to determining the aroma characteristics of Chinese steamed breads (CSBs) by using this approach. The aim of this work was to evaluate the key aroma compounds and their potential generation pathway in Chinese steamed bread produced with type I sourdough by a metabolomics approach. Based on the aroma characteristics analysis, CSBs produced with type I sourdough and baker’s yeast were clearly distinguishable by principal component analysis (PCA) scores plot. A total of 13 compounds in sourdough-based steamed breads were given the status of discriminant markers through the untargeted metabolomics analysis. According to the odor activity values (OAVs) of discriminant aroma markers, ethyl acetate (fruity), ethyl lactate (caramel-like), hexyl acetate (fruity), (E)-2-nonenal (fatty) and 2-pentylfuran (fruity) were validated as the key volatile compounds in the breads produced with type I sourdough as compared to the baker’s yeast leavened steamed bread. The metabolite analysis in proofed dough indicated that esters are mainly generated by the reaction between acid and alcohol during steaming, and aldehydes are derived from the oxidation of palmitoleic acid and linoleic acid during proofing and steaming.

How ingredients influence furan and aroma generation in sponge cake

A wide range of compounds can be formed during thermal processing of food, some of which are relevant for aroma (e.g., furfural), while others are of great health concern (e.g., furan). This paper presents the study of formulation as affecting the simultaneous generation of furan and furfural, along with other aroma quality markers, in sponge cake by means of headspace trap/GC-MS. Ingredients were screened according to their category (fat, salt, sugar, egg-based). Glucose-containing formulation resulted in the highest content of furan and furfural (12.5 ± 0.5 ng g^-1 and 9.2 ± 0.2 μg g^-1, dry basis, respectively), while their lowest amount was found in the egg-white recipe (3.1 ± 0.1 ng g^-1 for furan and 0.287 ± 0.078 µg g^-1 for furfural, dry basis). The latter also related negatively to all studied compounds. This work will be useful for developing novel strategies to deliver safe foods with appealing organoleptic attributes.