Effect of fermented and unfermented buckwheat flour on functional properties of gluten-free muffins

Identification and Bioaccessibility of Maillard Reaction Products and Phenolic Compounds in Buckwheat Biscuits Formulated from Flour Fermented by Rhizopus oligosporus 2710

The identification and potential bioaccessibility of phenolic compounds using the highly sensitive micro-HPLC-QTRAP/MS/MS technique and Maillard reaction products (MRPs) in buckwheat biscuits formulated from flours, raw and roasted, fermented by Rhizopus oligosporus 2710 was addressed in this study after in vitro digestion. The content of the analyzed MRPs such as furosine, FAST index, and the level of melanoidins defined by the browning index was increased in the biscuits prepared from fermented flours as compared to the control biscuits prepared from non-fermented ones. After in vitro digestion higher content of furosine was observed in control and tested biscuits providing its high potential bioaccessibility. The fermented buckwheat flours used for baking affected the nutritional value of biscuits in comparison to the control biscuits in the context of the twice-increased FAST index. More than three times higher value of the browning index was noted in control and tested biscuits after digestion in vitro indicating the high bioaccessibility of melanoidins. Our results showed the presence of ten phenolic acids and eight flavonoids in the investigated biscuits. Among phenolic acids, vanillic, syringic, and protocatechuic were predominant while in the group of flavonoids, rutin, epicatechin, and vitexin were the main compounds in analyzed biscuits. Generally, the lower potential bioaccessibility of phenolic acids and higher potential bioaccessibility of flavonoids was found for biscuits obtained from buckwheat flours fermented by fungi compared to control biscuits obtained from non-fermented flours. Fermentation of buckwheat flour with the fungus R. oligosporus 2710 seems to be a good way to obtain high-quality biscuits; however, further research on their functional properties is needed.

Buckwheat hull, a valuable bakery product ingredient: assessment of bioaccessible phenolics and antioxidant capacity

In this study, the bioaccessible total phenolic compounds (TPC) and antioxidant capacity (AC) of commonly consumed bakery products enriched with raw (BH) or roasted (RBH) buckwheat hull were evaluated. The soluble and insoluble fractions obtained after in vitro enzymatic digestion of mixed rye/wheat bread with 4% of RBH (BRBH), wheat bread with 3% of BH (BBH), and their control counterparts were separated (C-BRBH and C-BBH, respectively). The addition of buckwheat hull, raw and roasted, significantly increased the values of analyzed parameters compared to control samples. Before the digestion, the highest values of TPC and AC were found for bread with 4% of RBH. After in vitro digestion of the bakery products, the content of TPC and AC in the soluble fraction was 75–90% higher compared to the values found in the undigested fraction. Generally, a decrease in the bioaccessibility index of enriched bakery products compared to control samples was observed. The obtained results indicate that buckwheat by-products may be used as a valuable ingredient for commonly used bakery products. Also, it was shown that the in vitro digestion model may be of relevance in assessing the bioaccessibility of bioactive compounds in commonly used bakery products.

Influence of Morphostructural Elements for Buckwheat (Fagopyrum esculentum Moench) Productivity in Different Agricultural Systems

The research was carried out at Vokė Branch of the Institute of Agriculture of Lithuanian Research Centre for Agriculture and Forestry in 2018–2019. The objective of this study was to determine the influence of the relative proportion of stems, leaves and flowers on biomass formation and grain yield in organic and conventional farming systems. The study found that buckwheat produced one-third more biomass in the conventional farming system than in the organic farming system. Differences between buckwheat cultivars were more distinct due to biomass formation than grain yield. The research determined that the productivity (biomass and grain yields) of buckwheat was dependent on the proportion of morphological elements in plants and the process of biomass formation and grain yield in organic and conventional agricultural systems. Biomass yields depended on the relative number of stems in both farming systems. Grain yield depended on the ratio of flowers in the morphostructure; however, statistically significant correlations were found only in the organic farming system.

Phytochemicals and Antioxidant Activity in Oat-Buckwheat Dough and Cookies with Added Spices or Herbs

The aim of this study was to determine the phytochemicals and antioxidant activity in oat-buckwheat doughs and cookies with the addition of ten selected spices or herbs (2 g/100 g flours weight basis). The used spices and herbs, as was expected, showed a wide range of bioactive molecules, namely phenolic acids and flavonoids, and they are a rich source of components with antioxidant potential. All analysed oat-buckwheat dough showed higher antioxidant activity potential and higher total phenolic content (TPC) compared to cookies. The highest TPC was found in clove, both dough and cookies, with its addition showing the highest ferric reducing antioxidant power. Generally, cookies with the addition of spice/herbs showed higher phytochemical contents and antioxidant activity compared to oat-buckwheat cookies without the condiment. The technology of obtaining confectionery products, like oat-buckwheat cookies, that will favor the protection of bioactive compounds should still be improved.

In Vitro Expanded Bioaccessibility of Quercetin-3-Rutinoside and Quercetin Aglycone from Buckwheat Biscuits Formulated from Flours Fermented by Lactic Acid Bacteria

The expanded bioaccessibility of rutin (Ru) and quercetin (Q) from buckwheat biscuits (BBs) formulated from liquid-state fermented flours by selected lactic acid bacteria (LAB) were determined after gastrointestinal digestion. Fermentation of buckwheat flours caused a LAB-dependent variation in Ru and Q content. BBs baked at 220 °C for 30 min showed lower content of Ru and Q, and no correlation was found between the content of these compounds in fermented flours and BBs. The expanded bioaccessibility of Ru from BBs was low when its content in the soluble and insoluble fractions remaining after digestion in vitro was taken into account. Contrary results were found for Q bioaccessibility which had an index greater than 1, indicating the high Q bioaccessibility from BBs. Since very low Q content was noted in the insoluble fraction remaining after BBs digestion, the high Q bioaccessibility was determined to be due to its concentration in the soluble fraction.

Biscuits from Fermented Roasted Buckwheat Flour - Phenolics Profile and Bioaccessible Angiotensin Converting Enzyme Inhibitory Activity

The bioaccessible angiotensin converting enzyme (ACE) inhibitory activity of biscuits formulated from roasted common buckwheat flour after fermentation by select bacteria was studied. The same content of total phenolic compounds was found in fermented flour and in biscuits obtained from them. Generally, fermentation of flour did not changes the ACE inhibitory activity, whereas baking process significantly increased the ACE inhibitory activity of examined products. The potential bioaccessible ACE inhibitory activity from biscuits was very high. Phenolic acids such as protocatechuic, vanillic and syringic acids as well as flavonoids: kaempferol and epicatechin in the digested buckwheat biscuits have the highest impact on ACE inhibitory activity. A high significant correlations were found between IC50 and total phenolic compounds of fermented flours, biscuits before and after digestion. The data obtained in this study closely associates phenolic compounds with ACE inhibitory activity.

The Application of Lamiaceae Lindl. Promotes Aroma Compounds Formation, Sensory Properties, and Antioxidant Activity of Oat and Buckwheat-Based Cookies

Aroma plays an important role in designing innovative functional foods. This study aimed to study the influence of incorporating herbs from the Lamiaceae family (sage, mint, rosemary, oregano, thyme) on aroma compound formation and sensory properties in oat-buckwheat products. DPPH, FRAP and PCL have been used to describe possible antioxidant activity changes and reduce power of cookies after Lamiaceae Lindl. addition. The volatiles analysis by HS-SPME-GC/MS, has shown that Lamiaceae addition significantly influences the volatiles composition (29 molecules) with a predominance of molecules with a positive sensorial impression. Cookies elaborated with herbs were characterized by a greater share of monoterpenes (e.g., limonene, eucalyptol), in the volatile profile than in control cookies. These compounds’ occurrence was closely correlated with the appearance of herbal odor and taste among sensory attributes in cookies with herbs addition. In contrast, a decrease of negative oil aroma and the bitter aftertaste was noted by a sensory panel. Moreover, in cookies of mint and rosemary, hexanal share decreased about 13 and 9.7-times, respectively. Considering all presented experiments, rosemary addition was the most effective in forming a positive aroma profile with high sensory acceptance and increased functional properties.

Buckwheat Secondary Metabolites: Potential Antifungal Agents

Research groups have put significant emphasis on the evaluation of nutritional, health-promoting, and other biological activities of secondary metabolites from buckwheat. Among these phytochemicals, phenolic and lipophilic antioxidants, particularly, phenolic acids, flavonoids, and tocopherols, have been the focus of the latest studies since antioxidant activity has recently been associated with the possibility of inhibiting fungal growth and mycotoxin biosynthesis. The mycotoxin contamination of cereal and pseudocereal grains caused primarily by Fusarium, Penicillium, and Aspergillus species poses a significant hazard to human health. Therefore, efforts to examine the involvement of plant antioxidants in the biosynthesis of mycotoxins at the transcriptional level have emerged. In addition, hydrophobic interactions of buckwheat phenolics with cell membranes could also explain their capacity to reduce fungal development. Eventually, possibilities of enhancing the biological activity of cereal and pseudocereal phytochemicals have been studied, and sourdough fermentation has been proposed as an efficient method to increase antioxidant activities. This effect could result in an increased antifungal effects of sourdough and bakery products. This review reports the main advances in research on buckwheat phenolics and other antioxidant phytochemicals, highlighting possible mechanisms of action and processes that could improve their biological activities.

ACE Inhibitory Properties and Phenolics Profile of Fermented Flours and of Baked and Digested Biscuits from Buckwheat

The angiotensin converting enzyme (ACE) inhibitory activity and phenolics profile of fermented flours and of baked and digested buckwheat biscuits was studied. The fermentation of buckwheat flour by select lactic acid bacteria (LAB) caused a decrease in ACE inhibitory activity as compared to the non-fermented flour. The baking process significantly reduced the ACE inhibitory activity of biscuits obtained from fermented flours, whereas digestion significantly increased these properties. In non-fermented and fermented flours and buckwheat biscuits before and after in vitro digestion samples, ten phenolic acids and eight flavonoids were found. Highly significant correlations were found between sample concentration of 50% inhibition of ACE (IC50) and total phenolic compounds of fermented flour and biscuits before and after digestion for each applied LAB, thus indicating a link between phenolic compound content and ACE inhibitory activity. In the digested biscuits, the input to ACE inhibitory activity was provided by p-coumaric, sinapic, syringic, vanillic, and protocatechuic acids as well as by kaempherol, quercetin, apigenin, and orientin. Therefore, it can be concluded that cumulative action of those phenolic acids and flavonoids released after digestion is responsible, in part, for the bioaccessible ACE inhibitory activity of buckwheat biscuits.

Assessment of the glycaemic index, content of bioactive compounds, and their in vitro bioaccessibility in oat-buckwheat breads

This study addressed determinations of the glycaemic index (GI), antioxidant capacity (AC), and phenolics content (TPC) of oat, buckwheat, and mixed oat/buckwheat breads. The bioaccessibility of TPC and the AC of breads were studied after in vitro digestion. The lowest values of the GI were determined for oat bread, whereas breads with the highest content of buckwheat flour had the highest AC. The digestion of breads showed that most of the TPC were found in the soluble fraction, but the phenolic compounds were still present also in the insoluble fraction after digestion. It was concluded that the mixed oat-buckwheat breads may serve as products with a medium GI, as a source of TPC, and as products with a high AC. It should be noted that enzymatic digestion or fermentation by microbiota could potentially enhanced breads antioxidant activity during digestion in the gastrointestinal tract.

Lactic Acid Fermentation of Cereals and Pseudocereals: Ancient Nutritional Biotechnologies with Modern Applications

Grains are a substantial source of macronutrients and energy for humans. Lactic acid (LA) fermentation is the oldest and most popular way to improve the functionality, nutritional value, taste, appearance and safety of cereal foods and reduce the energy required for cooking. This literature review discusses lactic acid fermentation of the most commonly used cereals and pseudocereals by examination of the microbiological and biochemical fundamentals of the process. The study provides a critical overview of the indispensable participation of lactic acid bacteria (LAB) in the production of many traditional, ethnic, ancient and modern fermented cereals and beverages, as the analysed literature covers 40 years. The results reveal that the functional aspects of LAB fermented foods are due to significant molecular changes in macronutrients during LA fermentation. Through the action of a vast microbial enzymatic pool, LAB form a broad spectrum of volatile compounds, bioactive peptides and oligosaccharides with prebiotic potential. Modern applications of this ancient bioprocess include the industrial production of probiotic sourdough, fortified pasta, cereal beverages and "boutique" pseudocereal bread. These goods are very promising in broadening the daily menu of consumers with special nutritional needs.

Physicochemical evaluation of corn extrudates containing varying buckwheat flour levels prepared at various extrusion temperatures

This study analyzed the characteristics (physicochemical properties as well as antioxidant activity) of corn grit extrudates containing buckwheat flour at various levels (0, 10, 20 and 30% w/w) extruded at various temperatures (130, 150 and 170 °C). Effect of roasting (92 °C for 15 min) on the extrudates was also studied. Buckwheat incorporation at different levels mainly increased the diameter, a* value (indicating redness), phenolic content and antioxidant capacity, while decreased bulk density and water absorption index of the extruded products. On the other hand, increment in extrusion temperature primarily increased the L* values (lightness), a* values and antioxidant activity but decreased the phenolic content of extrudates. Roasting improved the flavor and texture of the extrudates which was desirable. Extrudates prepared from corn grit with incorporation of buckwheat up to 20% level and extrusion cooking at 150 °C showed best sensory scores.