Shift of Volatile Organic Compounds (VOCs) in Gluten-Free Hemp-Enriched Sourdough Bread: A Metabolomic Approach

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.

Effect of the storage process on quality characteristics of hemp-enriched "tsoureki" a rich-dough baked Greek product

The effects of the storage process on the quality characteristics of a hemp-enriched "tsoureki" (a rich-dough baked Greek product, rich-dough baked product [RDBP]) were investigated. The wheat flour was substituted with defatted hemp flour at selected ratios (0%-50% hemp:wheat flour). The baked products were stored at 25°C and at specific time intervals (0, 1, 4, 7, 10, and 14 days), and their properties were determined, including moisture content, water activity, structure, texture, color, total phenolic content (TPC), and antioxidant activity. Moreover, analyses of phenolic compounds were performed using quadrupole time of flight liquid chromatography-mass spectroscopy, identifying 14 compounds. Both the first-order kinetic model and modified Avrami equation, including the hemp-to-wheat ratio effect in the rate constant, well described the changes in the quality characteristics. The results showed that storage time and hemp incorporation significantly affected the quality of the product. Water activity decreased from 0.901 to 0.859, whereas moisture content decreased from 30.52%-32.33% (0 days) to 26.97%-27.02% w.b. (14 days) with storage time for all hemp additions. Hardness was greatly affected by hemp flour addition and approached 14.72 and 17.85 N after 14 days of storage for 30% and 50% substitutions, respectively. Springiness and cohesiveness decreased with hemp addition and storage time. The color difference of the hemp-enriched products compared to the control sample increased during storage. TPC increased due to the addition of hemp flour, whereas 14 compounds were identified. Based on property correlation, the hemp-enriched RDBP-tsoureki held its high-quality characteristics for 7 days of storage and contained a significant amount of bioactive compounds. PRACTICAL APPLICATION: Industrially produced, defatted hemp is a promising byproduct that can be used to nutritionally enhance baked goods. Modeling results can be used for the prediction of the properties that define product storage ability and also that the hemp-enriched, rich dough-baked Greek "tsoureki" could be produced while maintaining total phenolic content and antioxidant activity during 7 days of storage. These findings are expected to be used in the future in baked goods industry applications to produce goods with an improved nutritional profile.

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.

Role of tailored sourdough fermentation in the flavor of wholegrain-oat bread

Sourdough technology has been known for its role in the improvement of texture, flavor, and quality of mainly wheat and rye-based breads for decades. However, little is reported about its use in the improvement of whole-grain oat bread, especially concerning flavor formation, which is one major consumer drivers. This study investigated the effects of sourdough obtained by different lactic acid bacteria and yeast starters consortia on the texture and flavor of 100% oat bread. Four different consortia were selected to obtain four oat sourdoughs, which were analyzed to assess the main features due to the different starter fermentation metabolism. Sourdoughs were added to breads as 30% dough weight. Bread quality was technologically monitored via hardness and volume measurements. Sourdough breads were softer and had higher specific volume. The sensory profile of sourdoughs and breads was assessed by a trained panel in sensory laboratory conditions, and the volatile profile was analyzed by HS-SPME-GC-MS. Sourdoughs were rated with higher intensities than untreated control for most of attributes, especially concerning sour aroma and flavor attributes. Sourdough breads were rated with higher intensities than control bread for sour vinegar flavor and total odor intensity, in addition they had richer volatile profile. Our results confirmed that sourdough addition can lead to an enhanced flavor, moreover, it demonstrated that the use of different consortia of lactic acid bacteria and yeast strains leads to the improvement of texture and altered sensory profile of whole-oat bread.

A comprehensive review on hempseed protein: Production, functional and nutritional properties, novel modification methods, applications, and limitations

With the global population on the rise, challenges in meeting protein demands are amplified by recent crises, prompting a swift shift to alternative protein sources due to disruptions in the supply chain. Plant-based proteins are gaining momentum due to economic, cultural, and environmental considerations, aligning with the preference for sustainable diets and resulting in more affordable plant-based products. The distinction between drug and industrial hemp fuels demand for its nutritional value, digestibility, low allergenicity, and bioactive properties. Industrial hempseed, featuring minimal Δ9-Tetrahydrocannabinol (THC) content (<0.2 %), emerges as a promising crop, offering high-quality protein and oil. The de-oiled hempseed cake stands as an eco-friendly and promising protein source enriched with phenolic compounds and fiber. Ongoing research seeks to enhance techno-functional properties of hempseed protein, surmounting initial limitations for integration into various foods. A range of techniques, both conventional and innovative, optimize protein characteristics, while modifying plant-based protein structures augments their application potential. Modification approaches like ultrasound, high-pressure homogenization, conjugation, complexation, fibrillization, and enzymatic methods enhance hempseed protein functionality. The review critically evaluates the techno-functional attributes of hempseed protein and explores strategies for customization through structural modifications. Lastly, the review assesses its composition, potential as a plant-based source, addresses challenges, and discusses strategies for enhanced functionality.

Effect of Lactobacillus plantarum fermentation on the physicochemical properties and flavor of rice protein-carboxymethylcellulose complexes

BACKGROUND

Fermentation is known to enhance the nutritional profile and confer unique flavors to products. However, the resultant effects on stability and physicochemical properties remain unexplored.

RESULTS

This study aims to elucidate the influence of fermentation on the stability and organoleptic characteristics of a rice protein beverage stabilized by carboxymethyl cellulose (CMC). The findings revealed that the average aggregate size escalated from 507 to 870 nm, concurrently exhibiting a significant increase in surface potential. The aggregation enhancement was substantiated by evident morphological changes and confocal laser scanning microscopical (CLSM) observations. A negative correlation was discerned between the physical stability of the beverage and fermentation duration. Moreover, flavor analysis of the beverage post a 3 h fermentation period highlighted an increase in aromatic ester compounds, thereby intensifying the aroma.

CONCLUSION

The study corroborates that fermentation can detrimentally influence product stability while concurrently improving its flavor profile. By establishing a mix ratio of 10:1 for rice protein and CMC and forming a relatively stable system through electrostatic interaction at a pH of 5.4, a flavorful rice protein beverage can be derived post 3 h-fermentation process. These findings offer insights into the impact of varying fermentation durations on the stability and flavor of polysaccharide-based rice protein beverages. © 2023 Society of Chemical Industry.

Utilization of industrial hemp by-product defatted seed flour: effect of its incorporation on the properties and quality characteristics of 'tsoureki', a rich-dough baked Greek product

BACKGROUND

A rich-dough baked Greek product named 'tsoureki' was prepared using non-gluten hemp seed flour at ratios of 0:100, 10:90, 30:70, and 50:50. The effects of hemp flour addition on the properties of 'tsoureki', including physicochemical properties (moisture content, water activity, sorption phenomena), structural properties, textural properties, total phenolic content, antioxidant activity, and sensorial characteristics, as well as the macroscopic structure and morphological characteristics, were studied.

RESULTS

Hemp flour addition affected dough rheology, showing tan δ values < 1, a decrease in both G' and G″ values, while both flow behavior and consistency indices were also significantly affected, which might have an influence on the final baked goods. The Guggenheim-Anderson-de Boer model satisfactorily described sorption data, while both hemp addition and temperature had a significant effect. A significantly higher hardness of 11.55 N, a lower specific volume of 2.65 cm³  g^-1 , and a lower porosity of 0.676 were observed at high hemp additions. The hemp flour level influenced the color of the crumb and crust, and the total color difference (ΔE) increased significantly with the increase in hemp flour. Hemp flour additions were detectable by the naked eye, with an obvious color difference between control and hemp-containing samples. Moreover, the phenolic content and antioxidant capacity were increased, as were some organoleptic characteristics, such as the bitter aftertaste. Concurrently, overall acceptability decreased significantly.

CONCLUSION

Overall, the incorporation of gluten-free defatted hemp seed flour in 'tsoureki' formulations seems to be a promising alternative for improving quality of such rich-dough baked products. © 2022 Society of Chemical Industry.

Hemp: A Sustainable Plant with High Industrial Value in Food Processing

In the era of SDGs, useful plants which provide valuable industrial outputs and at the same time pose less impact on the environment should be explored. Hemp seems one of the most relevant gluten-free crop plants to meet such requirements. Its high nutritional value is comparable to soy. Moreover, almost the whole body of the hemp plant has a wide array of utility: industrial production of food, fiber, and construction materials. In view of environmental sustainability, hemp requires less pesticides or water in cultivation compared to cotton, a representative fiber plant. This short review investigates hemp's sustainability as a plant as well as its utility value as a highly nutritional material in the food industry. Recent application research of hemp protein in food processing includes plant milk, emulsifiers, fortification of gluten-free bread, plant-based meat production, as well as membrane formation. These studies have revealed distinctive properties of hemp protein, especially in relation to disulfide (S-S)/sulfhydryl (-SH)-mediated interactions with protein from other sources. While its cultivation area and industrial use were limited for a while over confusion with marijuana, the market for industrial hemp is growing rapidly because it has been highly reevaluated in multiple areas of industry. Conclusively, with its sustainability as a plant as well as its distinctive useful property of the seed protein, hemp has promising value in the development of new foods.

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.

The Exploitation of a Hempseed Byproduct to Produce Flavorings and Healthy Food Ingredients by a Fermentation Process

Following the One Health principles in food science, the challenge to valorize byproducts from the industrial sector is open. Hemp (Cannabis sativa subsp. sativa) is considered an important icon of sustainability and as an alternative food source. Hemp seed bran, in particular, is a byproduct of industrial hemp seed processing, which is not yet valorized. The success, and a wider market diffusion of hemp seed for food applications, is hindered by its unpleasant taste, which is produced by certain compounds that generally overwhelm the pleasant bouquet of the fresh product. This research concerns the exploration of hemp seed bran through fermentation using beneficial lactobacilli, focusing on the sensorial and bioactive traits of the products when they are subjected to bacterial transformation. By studying of the aromatic profile formation during the fermentation process the aim was to modulate it in order to reduce off-odors without affecting the presence of healthy volatile organic compounds (VOCs). Applying multivariate analyses, it was possible to target the contribution of processing parameters to the generation of flavoring and bioactive compounds. To conclude, the fermentation process proposed was able to reduce unpleasant VOCs, whilst at the same time keeping the healthy ones, and it also improved nutritional quality, depending on time and bacterial starters. The fermentation proposed was a sustainable biotechnological approach that fitted perfectly with the valorization of hemp byproducts from the perspective of a green-oriented industrial process that avoids synthetic masking agents.

Effect of formulations and fermentation processes on volatile organic compounds and prebiotic potential of gluten-free bread fortified by spirulina (Arthrospira platensis)

Gluten free (GF) foods, designed and marketed for the needs of people who are unable to metabolize gluten, in recent years have aroused growing interest that has led to the conquest of important market segments, with a strongly growing trend. Given the low protein content of standard GF flours, it is particularly important to fortify GF foods, and to study the effect that this process exerts on functional and sensorial characteristics. In this work, fortification of GF bakery goods was done with the addition of Arthrospira platensis (spirulina) flour. Two different dough formulations (with and without fortification) were fermented by four different processes, including spontaneous, single strains and sourdough starters. The baked products were then subjected to "consumer's tests". During the process, fermentation performances, prebiotic activity, and the VOC (Volatile Organic Compound) profiles were analyzed and compared through robust multivariate statistics. The results obtained evidenced that fortification led to a product with more abundant (medium organic acids) and exclusive bioactives (thymol, borneol, and nicotinic acid), which were correlated to the prebiotic activity of spirulina breads. This work, for the first time indicates that spirulina can be used to fortify GF bakery, improving also its functional potential.

Sourdough production: fermentation strategies, microbial ecology, and use of non-flour ingredients

Sourdough production is an ancient method to ferment flour from cereals for the manufacturing of baked goods. This review deals with the state-of-the-art of current fermentation strategies for sourdough production and the microbial ecology of mature sourdoughs, with a particular focus on the use of non-flour ingredients. Flour fermentation processes for sourdough production are typically carried out by heterogeneous communities of lactic acid bacteria and yeasts. Acetic acid bacteria may also occur, although their presence and role in sourdough production can be criticized. Based on the inoculum used, sourdough productions can be distinguished in fermentation processes using backslopping procedures, originating from a spontaneously fermented flour-water mixture (Type 1), starter culture-initiated fermentation processes (Type 2), and starter culture-initiated fermentation processes that are followed by backslopping (Type 3). In traditional recipes for the initiation and/or propagation of Type 1 sourdough productions, non-flour ingredients are often added to the flour-water mixture. These ingredients may be the source of an additional microbial inoculum and/or serve as (co-)substrates for fermentation. An example of the former is the addition of yoghurt; an example of the latter is the use of fruit juices. The survival of microorganisms transferred from the ingredients to the fermenting flour-water mixture depends on the competitiveness toward particular strains of the microbial species present under the harsh conditions of the sourdough ecosystem. Their survival and growth is also determined by the presence of the appropriate substrates, whether or not carried over by the ingredients added.

Metabolomics as a Tool to Elucidate the Sensory, Nutritional and Safety Quality of Wheat Bread-A Review

Wheat (Triticum aestivum) is one of the most extensively cultivated and used staple crops in human nutrition, while wheat bread is annually consumed in more than nine billion kilograms over the world. Consumers’ purchase decisions on wheat bread are largely influenced by its nutritional and sensorial characteristics. In the last decades, metabolomics is considered an effective tool for elucidating the information on metabolites; however, the deep investigations on metabolites still remain a difficult and longtime action. This review gives emphasis on the achievements in wheat bread metabolomics by highlighting targeted and untargeted analyses used in this field. The metabolomics approaches are discussed in terms of quality, processing and safety of wheat and bread, while the molecular mechanisms involved in the sensorial and nutritional characteristics of wheat bread are pointed out. These aspects are of crucial importance in the context of new consumers’ demands on healthy bakery products rich in bioactive compounds but, equally, with good sensorial acceptance. Moreover, metabolomics is a potential tool for assessing the changes in nutrient composition from breeding to processing, while monitoring and understanding the transformations of metabolites with bioactive properties, as well as the formation of compounds like toxins during wheat storage.

Volatilome changes during probiotic fermentation of combined soy and rice drinks

Plant-based drinks as a substitute for animal milk consumption are crucial products in the food industry. Soy and rice drinks are the most successful milk substitutes but are low in fiber and protein contents, respectively, whilst being rich in sugars. Generally, an improvement is foreseen; thus, apart from supplement addition, a natural occurring strategy is functionalizing the drinks by beneficial bacteria fermentation. The aim of this work is to develop novel plant-based drinks assessing different mixtures of soy and rice milks fermented with single or multi-strain probiotics (Lactobacillus fermentum, L. plantarum, L. helveticus, Bifidobacterium bifidum, and B. longum). The drinks were characterized to study bacterial performances, by means of culture-dependent and -independent techniques, and their volatilome, by means of solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis. Through multivariate analysis, these features were investigated and correlated to define accurate descriptors of the produced functional drinks. The results showed that combined drinks and multi-strain fermentation generated higher-value products. For example, combined drinks in comparison with single ones had a lower amount of toxic 2-acetyl-3,5-dimethylfuran and higher abundances of desirable compounds such as 2-butanone, 3-hydroxy and butanoic acid. Multivariate analysis of volatile metabolites and physiological parameters could offer a novel approach to assess the quality of functional plant-based drinks and result in a decisional tool for industrial applications.

Plant Volatiles of Lettuce and Chicory Cultivated in Aquaponics Are Associated to Their Microbial Community

In this work, an aquaponic cultivation system for Lactuca sativa (L.) and Chicorium intybus (L.) was compared to a hydroponic one, focusing on the main microbial populations related to food safety and their volatile compounds (VOCs), concluding with Spearman correlations among the microbes and VOCs. Different sections of both systems were sampled at the end of the commercial development of the plants. Plants cultivated in aquaponics were in general more contaminated than those from hydroponics, while for the cultivation waters a higher contamination of the hydroponics than aquaponics system was unexpectedly observed. Furthermore, the chicory exhibited higher levels of all microbial groups compared to lettuce grown under the same cultivation system. The results obtained also showed correlations between the distribution of some VOCs and microbial groups in the phyllosphere, while some examples of positive correlations between 2-nonanone (a positive phytostimulant compound) and anaerobic bacilli of the rhizosphere in lettuce were reported. So far, multivariate analysis of VOCs was able to discriminate on the basis of varieties but not on the cultivation systems. In conclusion, the microbial characteristics of the two ecosystems depended both on plant variety and cultivation method but further studies will need to deeply investigate the variables influencing the microbial quality of vegetable foods obtained by aquaponics. On the other hand, the analysis of the VOCs was more related to the microbial community of each plant variety considered, whatever the cultivation system. In precision agriculture, metabolomics may represent an opportunity to study the holobiome and through it the interactions between plants and their microbial populations, to possibly provide for a tool to assess the microbiological quality of vegetable foods obtained by aquaponic systems.

Comparing the Effectiveness of Three Different Biorefinery Processes at Recovering Bioactive Products from Hemp (Cannabis sativa L.) Byproduct

Hemp (Cannabis sativa L.) seeds are considered a nutritional powerhouse, rich in proteins and unsaturated fatty acids. The market for hemp seed food products is growing, due to the loosening of constraints in industrial cultivation. During the food processing chain, the external part of the seed is discarded, although it contains a significant amount of proteins. Converting this material into value-added products with a biorefinery approach could meet the ever-increasing need for sustainable protein sources while reducing food waste. In this study, creating value from hemp byproducts was pursued with three different approaches: (i) chemical extraction followed by enzymatic digestion, (ii) liquid fermentation by strains of Lactobacillus spp., and (iii) solid-state fermentation by Pleurotus ostreatus. The resulting products exhibited a range of in vitro antioxidant and antihypertensive activity, depending on the proteases used for enzymatic digestion, the bacterial strain, and the length of time of the two fermentation processes. These byproducts could be exploited as functional ingredients in the food, pharmaceutical, and cosmetic industries; the suggested biorefinery processes thus represent potential solutions for the development of other protein-containing byproducts or wastes.

Metabolomics-Based Study of the Effect of Raw Materials to the End Product of Tempe-An Indonesian Fermented Soybean

Tempe is a fermented soybean food from Indonesia, made by inoculating Rhizopus spp. onto cooked and dehulled soybean. Tempe has been a part of Indonesian culture since the 16th century and is now produced globally as a highly nutritious plant-based food. Despite a longstanding history on the production of tempe, very few studies have been reported to understand the effect of raw material to the end product metabolite composition. In this research, we applied GC/MS-based metabolite profiling to investigate the effect of various possible factors that might affect the final product (environmental factors, raw materials, and starter cultures). Representative samples were tempe produced by Indonesian industries, Japanese industries as well as laboratory made tempe. The results showed that both environmental factors and raw materials (soybean, water, and starter culture) contributed to the tempe metabolite profile. Here we found the possibility that starter cultures might play a greater role to determine the metabolite profiles compared to other tested factors. This research might provide useful insights for the larger scale industries to maintain the quality of tempe for the benefit of the consumers.

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.