Food Biophysics最新文献

Hydrocolloids are commonly used as additives to suppress retrogradation of starch-based foods. However, the impact of hydrocolloids on starch retrogradation differs for starches with different components. In this study, the pasting and retrogradation behaviours of tapioca (amylose/amylopectin ratio is 0.226) and potato starches (amylose/amylopectin ratio is 0.483) with different hydrocolloids (Arabic gum, carrageenan, guar gum, and xanthan gum) were thoroughly investigated using ultraviolet-visible spectroscopy, rapid viscometer analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The addition of hydrocolloids reduced the setback and R_1047/1022 values of tapioca starch, suggesting that both short- and long-term retrogradation of tapioca starch were inhibited. In addition, swelling capacity, freeze-thaw stability, and scanning electron microscopy analyses indicated that tapioca starch interacted with hydrocolloid molecules, forming a denser network structure, which enhanced the water retention and improved the freeze-thaw stability of tapioca starch gel. Compared with tapioca starch, potato starch with hydrocolloids exhibited a more relaxed network structure with large voids, and the hydrocolloids exhibited a weaker inhibitory effect on the retrogradation of potato starch owing to its high amylose/amylopectin ratio. These results provide a theoretical basis for the application of hydrocolloid additives to enhance the anti-retrogradation properties of starch-based foods with different amylose/amylopectin ratios.

In this study, the effect of ultrasonic treatment on sweet potato protein (SPP) was discussed. The structural and functional characteristics of SPP treated with different ultrasonic amplitudes (20–50%) were analyzed. The findings of the study suggested that the protein size and zeta potential decreased from 1711.00 nm and − 17.87 mV to 447.03 nm and − 42.52 mV (30% amplitude). Appropriate ultrasonic amplitude (30%) can significantly increase protein solubility (72.54%→79.89%) and free sulfhydryl group content (34.65→41.09 µmol/g). Surface hydrophobicity increased significantly by 34.71% at 40% amplitude. The structure of SPP was unfolded and intermolecular interactions were reduced by ultrasonic treatment, affecting the secondary structure and tertiary conformation of SPP, according to Fourier transform infrared spectroscopy, fluorescence spectroscopy and ultraviolet spectroscopy. The proportion of α-helix and random coil increased, while the proportion of β-sheet decreased. When the ultrasonic amplitude reached 30%, the emulsifying activity and stability of SPP were increased by 85.76% and 180.82%, respectively. Moreover, the microstructure and rheological characteristics of the SPP emulsion were investigated in order to assess the impact of ultrasonic treatment on the stability of the emulsion. The results demonstrated that the emulsion produced by the SPP that had undergone ultrasonically treatment had significantly improved emulsion stability due to the increased surface charge, improved network structure, and smaller and more uniform protein size. The study provides a theoretical foundation for promoting the use of SPP in food processing.

Preservation of vegetables by drying, freezing, and pickling often leads to alterations in their nutritional characteristics. To promote preservation, this research explores the design and examines the effects of Radio Frequency (RF) and starch-based nanocomposite (SISN) packaging on the quality of habanero peppers during refrigerated storage. RF device was designed and applied to treat peppers at frequencies of 15.5 MHz, 20.22 MHz, and 27.12 MHz for 2, 4, and 6 min. The frequency was varied using a microcontroller MOSFET equipped with a voltage-controlled oscillator (VCO), phase-locked loop (PLL), and a frequency synthesizer. The treated samples were packaged with SISN films made of Irish potato starch and African star apple nanoparticles in three thicknesses (15.6 μm, 21.22 μm, 30.4 μm) and stored for 30 days at 6 °C. Microbial and nutritional properties, including lycopene, carotene, total phenolic compounds, and antioxidant activity, were examined. The optimal process parameters were identified using the Box-Behnken Design methodology. Results showed thicker films had better barrier properties due to lower permeance values, while thinner films exhibited higher thermal stability due to their tightly packed structure. Samples treated at 27.12 MHz for 6 min showed superior nutritional properties and the lowest microbial counts (fungi: 2.9 × 10² CFU/g, bacteria: 3.5 × 10³ CFU/g) at p < 0.05. At optimal conditions (23.73 Hz, 2 min, 28.14 μm film), microbial counts were reduced (fungi: 3.67 × 10² CFU/g, bacteria: 4.76 × 10³ CFU/g) compared to the control. Under these conditions, lycopene (6.31 mg/kg), β-carotene (3.68 mg/kg), and vitamin C (87.61 mg/100 g) levels increased, while antioxidant activity slightly decreased to 147.47 µmol TE/100 g. Thus, applying RF treatment before SISN packaging effectively preserved the quality of habanero peppers and is recommended for vegetables preservation.

In view of the burgeoning market of plant-based foods, there has been a vigorous increase in research studies on the application of different plant proteins for structuring food colloids. Plant-based proteins extracted from pulses or leguminous grains, plant seeds, nuts, kernels, or leaves have found their applications as emulsifiers in designing colloidal emulsions and gels for structuring functional foods. Different extraction techniques such as alkaline, deep eutectic solvent (DES), enzymatic, or salt-assisted extraction can modify plant protein structure. These alterations can enhance interfacial adsorption, foaming, and emulsifying properties of the proteins. They additionally affect the rheological properties of the formulated protein gels. Additional processing using ultrasound, pulsed electric field (PEF), microwave, high-pressure, supercritical CO₂, or subcritical water at optimized conditions can enhance protein extraction yield and ameliorate its emulsifying and gelling properties by increasing protein unfolding and elevating its random structure. Conjugation of plant proteins with the polyphenols can alter the surface hydrophobicity, charge, and interfacial properties of the proteins, and elevate the viscosity and elasticity of emulsion gels. It additionally improves foaming properties of the proteins by adjusting their solubility. Plant protein-polyphenol conjugates have found their applications in formulating adhesives, fat replacers, and antioxidants in alternative protein foods. In this perspective, this review study discusses how plant protein extraction and conjugation with the polyphenols impact the structure of the proteins and the rheology of plant protein emulsions and gels. Potential applications of plant protein-polyphenol conjugates for formulating plant-based foods are also highlighted.

Traditional squid products often exhibit a firm texture, which adversely affecting their palatability. This study investigated the potential of ultrasound pretreatment and sous-vide cooking as alternatives to the conventional sodium tripolyphosphate pretreatment and high-temperature cooking methods, aiming to better preserve the color, tenderness, flavor, and overall sensory attributes of squid products. Results showed that treating squid with ultrasound at 200 W and 25 kHz for 15 min yielded tenderness comparable to that obtained from soaking in a 1% sodium tripolyphosphate solution for 2 h. After ultrasound treatment, the hardness of the squid initially decreased and then increased as sous-vide cooking time extended. The squid exhibited the lowest hardness and optimal color when cooked at 70 °C for 20 min. Compared to traditional high-temperature cooking, sous-vide cooking retained higher free amino acids content, which allowed more formation of umami and sweet-tasting amino acids. The radar plots from electronic nose detection also indicated that sous-vide process presented a more pronounced flavor profile. Therefore, the combination of ultrasound pretreatment and sous-vide cooking significantly enhanced the edible quality and flavor characteristics of squid, demonstrating substantial potential to replace traditional squid processing methods.

Chitosan nanoparticles loaded with tea tree essential oil (TTO-CHNPs) were fabricated and the effects of chitosan molecular weight (MW) (50, 200, and 500 kDa) on the physicochemical properties and biological activities of TTO-CHNPs were investigated. TTO was successfully encapsulated into chitosan nanoparticles with encapsulation efficiency (EE) ranging from 74.15 to 80.94%. TTO encapsulation significantly improved the antioxidant and antimicrobial activities of TTO-CHNPs. The chitosan MW significantly affected the antioxidant and antimicrobial activities of TTO-CHNPs and the preservation effect for mini-cucumbers coated with TTO-CHNPs. Among TTO-CHNPs with different MW of chitosan, those prepared using low MW of chitosan (TTO-LCHNPs) exhibited the highest EE of TTO, the greatest antibacterial activity against Staphylococcus aureus and antifungal activity against Botrytis cinerea in vitro, and the highest reduction in disease incidence and severity of B. cinerea inoculated mini-cucumbers. TTO-LCHNPs coating presented the best preservation effect on mini-cucumbers, extending their shelf life by 9 days.

This study presents a novel multifunctional hydrogel synthesized by crosslinking Chlorella protein using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/n-hydroxysuccinimide, aimed at extending the shelf life of perishable fruits like cherries. Structural, rheological, and scanning electron microscopy analyses revealed that Chlorella protein hydrogels (CPH) possess excellent solid-like properties and a stable porous structure. The water-holding capacity improved significantly from 67.11 ± 0.72% to 96.53 ± 0.61% with increasing CP concentration (10–22.5%, w/v). Additionally, CPH decomposition temperatures were ~ 150 °C (5% weight loss), demonstrating good thermal stability. Due to the ionization of -COOH and -NH₂ groups, the CPH showed excellent pH sensitivity, with low dissolution rates in acidic environments (64.97%) and significantly higher rates in alkaline environments (448.50%). Furthermore, the CPH inhibited the penetration of Staphylococcus aureus and Escherichia coli, and exhibited good free radical scavenging abilities against DPPH (74.50%) and ABTS^•+ (97.92%). In cherries preservation tests, CPH extended preservation time to 15 days compared to 5 days in the control group, effectively inhibiting decay, suggesting CPH is a promising choice for multifunctional fruit preservation.

Graphical abstract

Protein-polyphenol conjugates, formed through chemical modifications, can alter the structure of proteins, thereby enhancing their functional properties and enabling the development of novel ingredients for diverse applications. Despite this potential, the covalent conjugation of ovalbumin (OVA) with ferulic acid (FA) and the determination of their optimal binding ratios have not been previously studied. To address this gap, we investigated the formation of OVA-FA conjugates using an alkaline method and identified an optimal ratio of 0.9 g of FA per g of OVA. The resulting conjugates displayed substantial alterations in the secondary and tertiary structures of OVA, increased hydrophobicity, and a higher molar mass. These structural modifications significantly improved the solubility, emulsification capacity, and foam-forming ability of OVA, while also enhancing its antioxidant activity compared to the unmodified protein. These findings demonstrate the potential of OVA-FA conjugates as multifunctional emulsifiers with antioxidant properties, broadening their applications in the food and nutraceutical industries.

Mercury (Hg) and arsenic (As) are highly toxic metal(loid)s, and the consumption of food (particularly rice and seafood) represents a significant pathway for human exposure to these elements. Dietary habits, such as the intake of herbal tea and soup, may profoundly influence this exposure, which can be assessed through bioaccessibility. This study investigated the effects of various herbal tea ingredients on the bioaccessibility of Hg and As. Our findings revealed that certain ingredients significantly reduced Hg bioaccessibility from food, with reductions ranging from 30.1 to 90.2%; chrysanthemum exhibited the highest efficacy, followed closely by honeysuckle. Notably, inorganic mercury (iHg) bioaccessibility was more susceptible to reduction than methylmercury (MeHg) when co-digested with herbal tea ingredients. Only glabrous greenbrier and abrus herb effectively reduced bioaccessible As from food, with bioaccessibility decreasing in the following order: inorganic As (iAs) > dimethylarsinic acid (DMA) > arsenobetaine (AsB). These findings suggest that specific ingredients can mitigate human exposure to Hg and As, highlighting the necessity for further research into their chemical properties and functional implications.

Betacyanin and betaxanthin are well-known secondary metabolites of betalains in red beet (Beta vulgaris), which contribute to the natural red–purple and yellow–orange color. Various analytical techniques, such as chromatography and nuclear magnetic resonance spectroscopy, are currently available and have been performed to quantify the betalain content. However, evidence shows that these methods remain arguable because of their disadvantages, such as being time-consuming, labor-intensive, destructive, and producing chemical wastes. This study aimed to encompass the spectroscopic techniques through near-infrared (NIR) and mid-infrared (MIR) spectroscopy coupled with partial least squares regression PLSR analysis for rapid and nondestructive measurements of red beet powder betalain content. This study evaluated full and effective wavebands to determine the optimum model for predicting betacyanin and betaxanthin in red beet powder. The finding of effective wavebands was done by employing a variable important in projection (VIP) technique. This study demonstrated that betacyanin and betaxanthin were optimally predicted using NIR, with an R² of 0.92 and a RMSEP of 0.07 mg/g for betacyanin and R² of 0.83 with RMSEP of 0.04 mg/g for betaxanthin. This optimum model was achieved through the effective wavebands via VIP method. Thus, the proposed model is applicable for predicting betalain content in red beet powder nondestructively.