Impact of frozen storage time on the volatile profile of wheat bread crumb

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 Microwaved Brewer's Spent Grains on the Quality and Flavor Characteristics of Bread

To enable a wider utilization of co-products from beer processing and minimize the negative effect of added grain on bread quality, flavor, and other attributes, brewer's spent grains (BSG) are processed through microwave pretreatment, and then the microwave-treated BSG (MW-BSG) is added to bread. So far, there has been no investigation on the effect of microwave-pretreated BSG on bread quality and flavor. In this study, we examined the effects of diverse microwave treatment variables on the physicochemical structure of BSG and explored the consequences of MW-BSG on the quality and flavor of bread. The results showed that soluble dietary fiber and water-soluble protein levels in MW-BSG increased significantly (144.88% and 23.35%) at a 540 W microwave power, 3 min processing time, and 1:5 material-liquid ratio of BSG to water. The proper addition of MW-BSG positively affected the bread texture properties and color, but excessive amounts led to an irregular size and distribution of the bread crumbs. The result of electronic nose and HS-SPME-GC-MS analyses showed that the addition of MW-BSG modified the odor profile of the bread. A sensory evaluation showed mean scores ranging from 6.81 to 4.41 for bread containing 0-10% MW-BSG. Consumers found a maximum level of 6% MW-BSG acceptable. This study endeavors to decrease environmental contamination caused by brewing waste by broadening the methods by which beer co-products can be utilized through an innovative approach.

Exploring the Effect of Different Storage Conditions on the Aroma Profile of Bread by Using Arrow-SPME GC-MS and Chemometrics

In the present feasibility study, SPME Arrow-GC-MS method coupled with chemometric techniques, was used for investigating the impact of two different storage conditions, namely freezing and refrigeration, on volatile organic compounds (VOCs) of different commercial breads. The SPME Arrow technology was used as it is a novel extraction technique, able to address issues arising with traditional SPME fibers. Furthermore, the raw chromatographic signals were analysed by means of a PARAFAC2-based deconvolution and identification system (PARADISe approach). The use of PARADISe approach allowed for an efficient and rapid putative identification of 38 volatile organic compounds, including alcohols, esters, carboxylic acids, ketones, and aldehydes. Additionally, Principal Component Analysis, applied on the areas of the resolved compounds, was used to investigate the effects of storage conditions on the aroma profile of bread. The results revealed that the VOC profile of fresh bread is more similar to the one of bread stored in the fridge. Furthermore, there was a clear loss of aroma intensity in frozen samples, which could be explained by phenomena related to different starch retrogradation that occurs during freezing and refrigeration. However, considering the limited number of investigated samples, this study must be considered as a proof of concept; a more statistically representative sampling and further examinations of other properties, such as bread texture, need to be performed to better understand whether samples destined for eventual analysis should be frozen or refrigerated.

Evolution of volatiles and quality of Chinese steamed bread during storage at different temperatures

The aim of this work is to investigate the evolution of volatiles and quality of CSB during 4 d of storage at 4 °C and 25 °C, respectively. Rapidly increasing hardness and decreasing resilience were observed in CSB after 1 d of storage at 4 °C. However, relative soft CSB was found after 1 d of storage at 25 °C as a result of the lower rate of retrogradation. Volatiles were monitored by gas chromatography-mass spectrometer. Significant (P < 0.05) decrease of 4 esters and 2-pentylfuran were observed with prolonged storage time for CSB stored at both 4 °C and 25 °C. PCA analysis indicated that the storage temperature of 4 °C was beneficial to remain CSB volatiles during long storage time (2-4 d). These findings might be beneficial to retain more volatiles and quality and finally extend shelf-life of CSB.

Characterization of Key Odorants in Scallion Pancake and Investigation on Their Changes during Storage

To characterize key odorants in scallion pancake (SP), volatiles were extracted by solvent extraction-solvent assisted flavor evaporation. A total of 51 odor-active compounds were identified by gas chromatography-olfactometry (GC-O) and chromatography–mass spectrometry (GC-MS). (Z/E)-3,6-Diethyl-1,2,4,5-tetrathiane was detected for the first time in scallion food. Application of aroma extract dilution analysis to extracts showed maltol, methyl propyl disulfide, dipropyl disulfide and 2-pentylfuran had the highest flavor dilution (FD) factor of 4096. Twenty-three odorants with FD factors ≥ 8 were quantitated, and their odor active values (OAVs) were calculated. Ten compounds with OAVs ≥ 1 were determined as the key odorants; a recombinate model prepared from the key odorants, including (E,E)-2,4-decadienal, dimethyl trisulfide, methyl propyl disulfide, hexanal, dipropyl trisulfide, maltol, acetoin, 2-methylnaphthalene, 2-pentylfuran and 2(5H)-furanone, successfully simulated the overall aroma profile of SP. The changes in odorants during storage were investigated further. With increasing concentrations and OAVs during storage, hexanal became an off-flavor compound.