Optimisation of HS-SPME Parameters for the Analysis of Volatile Compounds in Baked Confectionery Products

Measurement of fluorotelomer alcohols based on solid phase microextraction followed by gas chromatography-mass spectrometry and its application in solid waste study

This work developed a method based on solid phase microextraction followed by gas chromatography/mass spectrometry (SPME-GC/MS) for the measurement of fluorotelomer alcohols (FTOHs) in gas samples. The method quantification limit (MQL) is 6-7 ng/L for 6:2 fluorotelomer alcohols (6:2 FTOH) and 8:2 fluorotelomer alcohols (8:2 FTOH). In contrast to common methods such as thermal desorption combined with GC-MS, it needs neither pre-concentration equipment nor large sample volume. The extraction-evaporation-GC/MS is commonly used in literature for FTOHs measurement in solids samples. We developed a method to measure FTOHs in solid samples by adding solvent extraction prior to headspace SPME-GC/MS. The extraction-headspace SPME-GC/MS method has a quantification limit of 40-43 ng per gram for 6:2 FTOH and 8:2 FTOH in solid samples. This is comparable to the MQLs for the extraction-evaporation-GC/MS method. Removing the solvent evaporation step decreased the risk of contamination and loss of analytes. The developed methods were successfully used in three examples of solid waste study: 1) measuring 6:2 FTOH and 8:2 FTOH above the MQL in gas emissions from a closed landfill, 2) finding 6:2 FTOH above MQL in 9 of 31 solid consumer products, and 3) finding that the release of 6:2 FTOH in simulated landfills containing popcorn bags was linear at a rate of 3.15 ng/g popcorn bags-day and that partial 6:2 FTOH was from the hydrolysis of precursors.

A New Dietary Fiber Can Enhance Satiety and Reduce Postprandial Blood Glucose in Healthy Adults: A Randomized Cross-Over Trial

BACKGROUND

Dietary fiber plays a potential role in regulating energy intake and stabilizing postprandial blood glucose levels. Soluble dietary fiber has become an important entry point for nutritional research on the regulation of satiety.

METHODS

this was a double-blind, randomized cross-over trial enrolling 12 healthy subjects to compare the effects of RPG (R+PolyGly) dietary fiber products (bread, powder, and capsule) and pectin administered with a standard meal on satiety, blood glucose, and serum insulin level.

RESULTS

Adding 3.8% RPG dietary fiber to bread significantly increased the volume, water content, hardness, and chewiness of bread compared to 3.8% pectin bread and white bread and significantly improved the sensory quality of bread. RPG bread had better appetite suppression effects at some time points than the other two groups and the best postprandial blood glucose lowering effects among the three groups. Administration of RPG capsules containing 5.6 g of RPG dietary fiber with meals improved satiety and reduced hunger compared to 6 g of RPG powder and 6 g of pectin, which had the greatest effect on suppressing appetite and reducing prospective food consumption. The peak level of serum glucagon-like peptide-1 (GLP-1) in the RPG capsule group (578.17 ± 19.93 pg/mL) was significantly higher than that in other groups at 0 min and 30 min after eating. RPG powder had the best effect in reducing postprandial blood glucose and increasing serum insulin levels; the total area under the curve (AUC) of serum insulin with RPG powder was higher than other groups (5960 ± 252.46 μU min/mL).

CONCLUSION

RPG dietary fiber products can improve the sensory properties of food, reduce postprandial blood glucose, and enhance satiety, especially in capsule and powder forms. Further research on the physiological effects of RPG dietary fiber is required to facilitate its use as a functional ingredient in food products.

Variations of main quality components of matcha from different regions in the Chinese market

Matcha has a unique aroma of seaweed-like, which is popular with Chinese consumers. In order to effectively understand and use matcha for drinks and tea products, we roundly analyzed the variation of main quality components of 11 matcha samples from different regions in the Chinese market. Most of matcha samples had lower ratio of tea polyphenols to amino acids (RTA), and the RTA of 9 samples of matcha was less than 10, which is beneficial to the formation of fresh and mellow taste of matcha. The total volatile compounds concentrations by HS-SPME were 1563.59 ~ 2754.09 mg/L, among which terpenoids, esters and alcohols were the top three volatile components. The total volatile compounds concentrations by SAFE was 1009.21 ~ 1661.98 mg/L, among which terpenoids, heterocyclic compounds and esters ranked the top three. The 147 volatile components with high concentration (>1 mg/L) and no difference between samples are the common odorants to the 11 samples of matcha. The 108 distinct odorants had differences among the matcha samples, which were important substances leading to the different aroma characteristics. Hierarchical cluster analysis (HCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) showed that 11 samples of matcha were well clustered according to different components. Japanese matcha (MT, MY, ML, MR, MJ) could be clustered into two categories. The aroma composition of Guizhou matcha (GM1, GM2) was similar to that of Japanese matcha, 45 volatile components (decanal, pyrazine, 3,5-diethyl-2-methyl-, 1-hexadecanol, etc. were its characteristic aroma components. The aroma characteristics of Shandong matcha and Japanese matcha (ML, MR, MJ) were similar, 15 volatile components (γ-terpinene, myrtenol, cis-3-hexenyl valerate, etc.) were its characteristic aroma components. While Jiangsu matcha and Zhejiang matcha have similar aroma characteristics due to 225 characteristic aroma components (coumarin, furan, 2-pentyl-, etc). In short, the difference of volatile components formed the regional flavor characteristics of matcha. This study clarified the compound basis of the flavor difference of matcha from different regions in the Chinese market, and provided a theoretical basis for the selection and application of matcha in drinks and tea products.

Aroma generation in sponge cakes: The influence of sucrose particle size and sucrose source

The influence of sucrose source and particle size was investigated in relation to the volatile and aromatic properties of sponge cakes. Six sponge cake formulations were studied using two sucrose sources (sugarbeet and sugarcane), at two particle sizes (large and small) with controls. Volatiles profiles and odour active compounds were identified by gas chromatography mass spectrometry and olfactometry. Sixty two volatile compounds were identified, incorporating twenty five odour active compounds/co-eluting compounds, with 5 odours perceived without any corresponding volatile. Particle size had the greatest impact on volatile abundance, with particle size especially influencing pyrazine abundance. Five odour active volatiles (methional, furfural, 2,3-dimethylpyrazine, heptanal and (E)-2-octenal) contributed most to the aroma of these sponge cakes. Small particle size particularly from sugarbeet yielded higher levels of some Maillard and caramelisation reaction compounds, such as furfural (spicy/ bready), where larger particle size supressed volatile abundance in comparison to the control.

Changes in the Volatile Profile of Wheat Sourdough Produced with the Addition of Cava Lees

The volatile fraction is of great importance for the organoleptic quality and consumer acceptance of bread. The use of sourdough improves the sensory profile of bread, as well as the addition of new ingredients to the fermentation. Cava lees are a sparkling wine by-product formed of dead microorganisms, tartaric acid, and other inorganic compounds, rich in antioxidant compounds as well as β-glucans and mannoproteins. The aim of this study was to evaluate the effect of different concentrations of Cava lees (0–2% w/w) on sourdough volatile compounds to re-valorize this by-product of the wine industry. Headspace solid-phase microextraction (HS-SPME) was optimized to study the volatile fractions of sourdoughs. The parameters selected were 60 °C, 15 min of equilibrium, and 30 min of extraction. It was found that the addition of Cava lees resulted in higher concentrations of volatile compounds (alcohols, acids, aldehydes, ketones and esters), with the highest values being reached with the 2% Cava lees. Moreover, Cava lees contributed to aroma due to the compounds usually found in sparkling wine, such as 1-butanol, octanoic acid, benzaldehyde and ethyl hexanoate.

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.

The role of sodium chloride in the sensory and physico-chemical properties of sweet biscuits

Salt is included in many foods which consumers do not regard as salty. This "hidden-salt" may offer functional benefits but is often overlooked in sodium reduction strategies. This study investigated its role in shortbread-like sweet biscuits (1.05 g NaCl/100 g). Sensory tests revealed significant flavour and texture differences after a salt reduction of 33% (0.86 g/ 100 g). This was explained by differences in the partitioning of hydrophobic aroma compounds into the headspace and a significant impact on structure. Texture analysis and X-ray-µCT measurements revealed a reduced hardness with larger and more air cells in salt-reduced biscuits. It is suggested that salt impacts on cereal proteins by altering their aggregation around flour particles and at bubble walls and that slower water loss occurs in salted matrices during baking. Hence, this study revealed the key properties significantly affected by salt reduction and proposes an explanation which will help to develop a targeted "hidden-salt" reduction strategy.

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.