The impact of various amounts of konjac glucomannan on the structural and physicochemical properties of gluten proteins/dough at different periods of frozen storage is evaluated in the present study. As frozen storage time was prolonged, the molecular weight and the free sulfhydryl content of gluten proteins and the tensile properties of frozen dough all decreased. The addition of konjac glucomannan reduced the variations in the structural and rheological properties of gluten proteins/dough. Frozen dough with 2.5% added konjac glucomannan showed the highest water binding capacity and retarded the migration of water. Scanning electron microscopy and differential scanning calorimetry results also revealed that adding konjac glucomannan reduced the cracks and holes in the dough and enhanced its thermal stability. The correlations between mechanical characteristics and structure parameters further indicated that konjac glucomannan could not only stabilize the structures of gluten proteins but also bind free water to form more stable complexes, thereby retaining the rheological and tensile properties of the frozen dough.

In this work, steam explosion (SE) was exploited as a potential hydrothermal-humification process of vegetable wastes to deconstruct their structure and accelerate their decomposition to prepare humified substances. Results indicated that the SE process led to the removal of hemicellulose, re-condensation of lignin, degradation of the cellulosic amorphous region, and the enhancement of thermal stability of broccoli wastes, which provided transformable substrates and a thermal-acidic reaction environment for humification. After SE treatment, total humic substances (HS), humic acids (HA_s), and fulvic acids (FA_s) contents of broccoli samples accounted for up to 198.3 g/kg, 42.3 g/kg, and 166.6 g/kg, and their purification were also facilitated. With the increment of SE severity, structural characteristics of HA_s presented the loss of aliphatic compounds, carbohydrates, and carboxylic acids and the enrichment of aromatic structures and N-containing groups. Lignin substructures were proved to be the predominant aromatic structures and gluconoxylans were the main carbohydrates associated with lignin in HA_s, both of their signals were enhanced by SE. Above results suggested that SE could promote the decomposition of easily biodegradable matters and further polycondensation, aromatization, and nitrogen-fixation reactions during humification, which were conducive to the formation of HA_s.

Three medicinal fungi were used to carry out solid-state fermentation (SSF) of wheat bran. The results showed that the use of these fungi for SSF significantly improved wheat bran’s nutritional properties including the extraction yield of soluble dietary fiber (SDF), total phenolic content (TPC), total flavonoid content (TFC), physical properties containing swelling capacity (SC) and oil absorption capacity (OAC), as well as antioxidant activities. Electronic nose and GC–MS analyses showed that fermented wheat bran had different volatiles profiles compared to unfermented wheat bran. The results suggest that SSF by medicinal fungi is a promising way for the high-value utilization of wheat bran.

The study investigated the extrusion modification of wheat bran and its effects on structural and rheological properties of wheat flour dough. Extruded bran showed better solubility of dietary fiber and structural porosity, leading to higher hydration and swelling power. Addition of extruded bran to dough caused water redistribution as an intensive aggregation of bound water to gluten matrix with reduced mobility. The bran–gluten interaction influenced by water sequestering caused partial gluten dehydration and conversion of β-turn into β-sheet, which demonstrated the formation of a more polymerized and stable gluten network. Farinographic data confirmed the promotion of dough stability with extruded bran addition at lower gluten content, while viscoelastic data suggested improved dough elasticity at all gluten contents by increasing elastic moduli and decreasing loss tangent. This study would be useful for interpreting the modification effect and mechanism of extrusion on cereal brans and provide valuable guidance for applying it as an effective modification technology on the commercial production of cereal bran and its flour products.

Fruits and vegetables represent important dietary sources of soluble dietary fiber (SDF), a functionally essential component that contributes substantially to human health maintenance. The molecular structure of SDFs in fruits and vegetables is influenced by food processing techniques, which can contribute to improving the physiological activities of SDFs and promoting health benefits. This article presents a systematic review of the effects of common processing methods mainly involving drying, heating, powdering, fermentation, etc., on the structural and nutritional properties of SDFs, particularly focused on structural changes in molecular weight, monosaccharide composition, and functional groups, as well as nutritional functions including obesity prevention, hypolipidemic and hypoglycemic properties, etc. Processing-induced structure variations in SDFs inevitably change their fermentability and gelling ability, promote the growth of beneficial bacteria and the production of short-chain fatty acids, enhance immunity, and reduce the risk of chronic diseases. This highlights the prebiotic efficacy and metabolic disease intervention potential of processing methods to moderate SDFs by altering their structure. This paper comparatively summarizes the effects of physical, physicochemical, and biological processing technologies on the common structural and nutritional properties of SDFs, aiming to provide theoretical guidance for the application of SDFs in the food industry. This paper not only provides a theoretical basis for the precise application of SDFs in functional foods but also reveals the potential mechanisms involved in regulating the structure of SDFs through processing technology to achieve nutritional intervention in metabolic diseases, which is an important guiding value for the development of food ingredients with specific health effects.