Food Structure-Netherlands最新文献

White and sweet potatoes can elicit different blood glucose responses depending on whether they are boiled or baked. This work investigated how microstructure and starch digestion in vitro relate to these differences. The main methods were INFOGEST’s semi-dynamic digestion protocol, Scanning Electron Microscopy and Confocal Laser Scanning Microscopy. The cooking method impacted microstructure, thereby significantly influencing starch digestion. Boiling and baking led to similar types of microstructural changes, including cell expansion and separation and disruption to cell walls, with the differences lying on the magnitude of such changes. Hydrolysis of white potato starch into oligosaccharides during oro-gastric digestion stabilized at around 75% when boiled compared to 50% when baked. In sweet potato, hydrolysis during this stage represented 30% and 40% of the total starch after boiling or baking, respectively. Overall, the effect can be summarized as boiled white potato > baked white potato > baked sweet potato > boiled sweet potato. Our results show how structural transformations that occur during cooking can drive differences in starch release and hydrolysis during in vitro digestions. This work therefore provides a structural and biochemical basis to better understand the impact of boiling and baking on the glycemic responses to these foods.

The aim of this study was to investigate the impact of the addition of a non-gelling non-ionic surfactant, Tween 20 (Tw20), at varying weight ratios with monoglycerides, MGs (0 – 20 g Tw20 to 10 g of MGs as structurant /100 g olive oil) in the crystalline network of the MGs-based oleogels. Several analytical methods such as differential scanning calorimetry (DSC), confocal and polarized optical microscopy, rheometry, and infrared spectroscopy were employed for the characterization of the oleogel structures. The DSC and FT-IR provided evidence that Tween 20 affects the MGs network structure in the oleogels. With addition of Tween 20 the crystal size and the melting/crystallization temperatures of the MGs crystal polymorphs were altered, along with a strengthening of the oleogel structure. Moreover, the presence of Tween 20 in the MGs oleogels accelerated the transformation of the higher free energy crystal forms (α-crystals) to the more thermodynamically stable β-polymorph of the MGs. Apparently, an oil-in-oil emulsion gel is being formed with the MG crystalline entities acting as Pickering particles around the oil/Tween 20 droplets in the oleogel structure. These findings provide valuable information on the synergistic effect of a non-ionic surfactant on monoglyceride-based oleogels, which could be beneficial in constructing multi-component lipid-phases for potential food or cosmetic applications.

This study prepared a series of freeze-dried sponges with different pectin-glucose concentrations at two shelf temperatures (−20 °C and 60 °C) to simulate the specific roles of pectin and glucose in the microstructure and textural properties of freeze-dried restructured fruit products. Pectin polysaccharide is mainly responsible for the construction of scaffolds after freeze-drying. When the content of pectin is more than 1.5% pectin, the occurrence of structural collapse could be significantly inhibited. The small molecule glucose is mainly responsible for the mechanical strength of the sponges. When the glucose increases from 4% to 12%, the mechanical strength of the sponge systems rises from 400 to 1400 g. Sponges with higher pectin content (>3.0%) could prevent the structural shrinkage of systems with greater sugar content (12%) or higher shelf temperature (60 °C), suggesting a possibility to achieve shrink-free lyophilization at high shelf temperature by adding the content of pectin.

Oleogels are semi-solid lipid-based materials designed to replace solid and semi-solid fats in foods, cosmetics, and pharmaceuticals. A new method for oleogel preparation through nanofibers has opened new possibilities for polymers from synthetic and natural origins previously considered inadequate for oleogel preparation. However, the obtained oleogels were made from conventionally electrospun nanofibers, where the production process still has limitations or the oleogel preparation process required different steps, such as use of organic solvents and extensive drying steps. In this work, we present a new organic solvent-free method for preparing oleogels using nanofiber mats of polyethylene oxide obtained with an ultrasound-enhanced electrospinning (USES) device. After dispersing nanofibers in oil followed by a cold-milling process, we obtained oleogels at a concentration >10% nanofiber concentration in rapeseed, walnut, and flaxseed oils. All oleogels were composed of a jammed dispersion of nanofiber mat fragments that conferred the system a gel-like behavior with good thixotropic recovery. In general, oleogel rheological properties were affected by oil type and nanofiber concentration, even if all systems showed uniform plastic deformation at increasing strain amplitude. Our results show that the milling method here developed can be a useful approach for obtaining oleogels using nanofibers obtained with USES, without the need of high temperatures or fiber pretreatments.

To understand how amylose content and crystal type regulated the digestibility of starch–lipid complex nanoparticles, this study used waxy corn starch (WCS), normal corn starch (NCS) and high-amylose corn starch (HCS) with different amylose contents and NCS (A-type), potato starch (PtS, B-type) and pea starch (PS, C-type) with different crystal types to investigate the effects of amylose content and crystal type on the structure and digestibility of starch-lauric acid (LA) complex nanoparticles. A significant increase in complex index (CI), R_1047/1022, relative crystallinity, and enthalpy of gelatinization (ΔH) was found in starch-LA complex nanoparticles with amylose contents increasing. The increases in resistant starch (RS) and slowly digestible starch (SDS) contents of WCS-LA complex nanoparticles, NCS-LA complex nanoparticles and HCS-LA complex nanoparticles were 29.33%, 40.29% and 93.90% compared to their respective controls. Furthermore, PtS-LA complex nanoparticles (PtS-LANPs) showed the highest increase in CI, R_1047/1022, relative crystallinity, and ΔH compared to NCS-LA complex nanoparticles (NCS–LANPs) and PS-LA complex nanoparticles (PS-LANPs). For RS and SDS contents, the highest increased was found in PtS-LANPs (56.99%), followed by NCS–LANPs (40.29%) and PS-LANPs (31.44%) as compared to their respective controls. Results could provide basic data to prepare starch–lipid complex nanoparticles with desired digestibility.

We aimed to develop a low-saturated fat oleogel with a small amount of high-melting fat and elucidate its gelation mechanism. Fully hydrogenated rapeseed oil rich in behenic acid (FHR-B), fully hydrogenated rapeseed oil rich in stearic acid (FHR-S), fully hydrogenated fish oil extracted from sardines (FHF), fully hydrogenated beef tallow (FHBT), fully hydrogenated palm oil (FHP), and fully hydrogenated hard palm mid-fraction (FHHPMF) were used as oleogelators. The gelation ability, chemical composition, crystal morphology, polymorphism, and melting properties of the prepared samples were evaluated. FHR-B, FHF, FHP, and FHHPMF formed gels with 2 wt% or lower concentrations. High-melting fat with a high gelation ability formed fibrous crystals with a high aspect ratio, that is, whisker crystals, in canola oil. The crystal morphology was affected by the triacylglycerol composition. Moreover, high-temperature storage caused the separation of TAGs, affecting the crystal morphology. Hence, high-melting fats with complex TAG compositions showed different gelation behaviors depending on the storage temperature. We confirmed that FHHPMF exhibited exceptionally high gelation ability, forming a gel at only 0.5 wt%. Therefore, FHHPMF may be a suitable oleogelator for industrial use with a controllable saturated fatty acid content and waxy mouthfeel.

Four oil types (coconut oil, rapeseed oil, sunflower oil, and flaxseed oil) and glycerol monostearate-beeswax mixture (GMS-BW; 1:1), as an oleogelator, at different concentrations (5%, 7.5%, 10%, and 12.5% w/w) were used to fabricate oil foam. Due to the higher overrun (∼38–45%) and foam stability (lower oil loss, 6–8%), intermediate firmness (∼0.55–0.60 N), and smaller bubble size (∼28 µm), sunflower oil foam (SOF) and flaxseed oil foam (FOF) containing 12.5% oleogelator were chosen for further experiments. X-ray diffraction revealed that oil type had no significant effect on polymorphism. Furthermore, FOF sample presented higher melting and crystallization enthalpy than SOF related to the stronger network confirmed by a higher G′ value (130,000 Pa) and yield stress (130 Pa) as well as its longer linear viscoelastic region (P < 0.05). Over storage time, overrun and oil loss of both samples decreased especially at room temperature, whereas firmness increased due to the further crystals’ interactions.

In this study, coffee pulp cellulose (CPC) was recovered from the coffee pulp biomass generated during wet processing of Arabica coffee using the following sequential extractions. As for screening, the Microarray Polymer Profiling (MAPP) was used to characterize the gylco The alcohol-insoluble fraction (AIF) was obtained from dried coffee pulp following by dichloromethane and ethanol to remove fat-soluble components. Ammonium oxalate extraction yielded insoluble dietary fiber, and lignin was removed from the pectin-free fraction using hydrogen peroxide and sodium borohydride. The resulting coffee pulp cellulose (CPC) was obtained after drying. Pectin was not detected in the cellulose fraction, indicating that the extraction was only partially successful in purifying the soluble and non-soluble polysaccharides. Structural damage and the presence of lignin and hemicellulose were also observed in the cellulose, as evidenced by its shredded morphology and Fourier Transform Infrared spectra. Cellulosic coffee pulp-based hydrogels were fabricated with of CPC ranging from 0.25 to 1.00 g with alginate and pectin as hydrophilic polymers and cross-linked by calcium chloride. The hydrogel with the lowest CPC concentration demonstrated a porous structure that allowed water molecules to diffuse into the material, causing it to swell or increase in size. The hydrogel with 0.38 g CPC had the highest maximum swelling degree (MSD), while incorporating CPC at 0.50 g resulted in the longest durability, as determined by the integrity value. The study found that all formulations of the hydrogel exhibited no toxicity towards HaCaT cells. This suggests the possibility of the industrial recovery of cellulose from underutilized materials, providing a sustainable solution to supply chain challenges.

Protein denaturation can be exploited to modulate its physicochemical properties and create different micro- or nano- structures that could be used for the development of innovative protein-enriched food formulations. This study introduces a novel approach for the production of nanoparticles by denaturing whey protein isolate with ethanol. Whey proteins were subjected to water/ethanol mixtures containing up to 70% w/w ethanol, at varying pH values and NaCl concentrations, to prepare protein nanoparticles in a controlled manner. Confocal microscopy, ATR-FTIR spectroscopy, fluorescence spectroscopy, laser diffraction analysis, and dynamic light scattering were employed to investigate their impact on protein denaturation and nanoparticles’ characteristics. A steep decrease of hydrophobicity up to 50% w/w ethanol was found. A dependence between denaturation and lower pH values was observed. Confocal microscopy revealed that small changes in pH affected the protein’s microstructure, while controlling ethanol concentration allowed for the production of different nanoparticles within narrow pH ranges. High concentrations of NaCl led to extended aggregation even at low ethanol content, while nanoparticles were formed at low NaCl (50 mM) and 30% w/w ethanol. Overall, ethanol denaturation of whey proteins presents a promising technique for the formation of protein nanoparticles.

The impact of authentic storage conditions during shipping was tested on whey protein concentrate powders as environmental conditions heavily influence shelf-life performance. Most experimental studies are conducted at constant conditions of temperature and/or humidity whereas in real shipment conditions powders are often transported all over the world in ships which can experience vastly different temperatures and humidity with large amplitudes from day-time to night-time. Here, industrial whey protein concentrates and β-lactoglobulin powders were stored under cycled temperatures and relative humidity fashioned from authentic data collected on ships carrying dairy powders. Protein lactosylation and denaturation, browning index, particle surface and powder functional properties were measured in order to estimate functional and physicochemical modifications occurring close to authentic storage under shipping. It was observed that oscillation amplitudes tested had no impact on powders unlike the storage duration. The presence of residual lactose (1.5 %) in the whey protein powder induced lactosylation during storage leading to particle surface hydrophobicity and surface elasticity increases whereas for β-lactoglobulin powders (depleted in lactose), transformation of initial lactosylated proteins into advanced Maillard products was observed with no particle surface impact. The rehydration was not impacted regardless of the storage conditions and powder chemical composition.