Physicochemical Methods Used to Study Internal Structures of Liquid Binary Mixtures

Abstract

Different methods, based on application of studies of intensive physicochemical properties of liquid binary mixtures and ¹H-NMR spectral measurements, used in the analysis of intermolecular interactions and estimation of the internal structure of these mixtures and here reviewed.     

Physicochemical properties of tilapia (Oreochromis niloticus) actomyosin subjected to high intensity ultrasound in low NaCl concentrations

Effects of high intensity ultrasound (HIU) on physicochemical properties of tilapia (Oreochromis niloticus) actomyosin in low NaCl concentrations were investigated. The protein content extracted in low NaCl concentrations (0.1–0.3 M NaCl) increased with increasing HIU intensity up to 20.62 W/cm² (p < 0.05). The effect of HIU on actomyosin extractability in high NaCl concentrations (0.6 and 1.2 M NaCl) was less obvious. Ca²⁺-ATPase activity and total sulfhydryl (SH) group content decreased in both 0.2 and 0.6 M NaCl. HIU showed more pronounced effect on oxidation of the SH groups in 0.6 M NaCl, while the reactive SH content at 0.2 M NaCl increased after a prolonged exposure to HIU, suggesting conformational changes induced by HIU. Surface hydrophobicity of actomyosin in 0.6 M NaCl increased with increasing ultrasonic intensity and exposure time to a higher degree than that in 0.2 M NaCl. A greater absolute value of the zeta potential of actomyosin subjected to HIU were also observed. The HIU treatments decreased the turbidity of actomyosin incubated at 40 and 60 °C. A drastic increase in the solubility of myosin heavy chain (MHC) and actin with 0.2 M NaCl were evident when HIU treatments were applied, but degradation of MHC occurred in both 0.2 and 0.6 M NaCl. Based on particle size and microstructure, actomyosin in 0.6 M NaCl underwent more disruption by HIU than that in 0.2 M NaCl. HIU induced protein unfolding and protein dissociation, enabling better extraction in a lower NaCl concentration.     

Evaluation of poly(L-lactic acid) (PLLA) rapid indicator film on deterioration degree of Refined,Bleached and Deodorised Malaysian Tenera palm olein oil (RBDPO) during long-term repetitive deep-fat frying

Palm olein oil is widely used as a medium for deep-frying purposes in the domestic and commercial sectors. However, repetitive usage beyond the recommended cycle leads to significant deterioration and spoilage of the oil. Therefore, this research investigated the effect of long-term repetitive deep-fat frying on the physicochemical properties of Refined, Bleached and Deodorised Malaysian Tenera Palm Olein oil (RBDPO) as well as the suitability of poly(L-lactic acid) (PLLA) film as a potential rapid indicator to determine the spoilage level of recycled palm olein oil. The study was carried out using three different RBDPO conditions; RBDPO without potatoes (RBDPO-1), RBDPO with potatoes (RBDPO-2), and RBDPO with Afdhal Oil (AO, an oil additive chemical) and potatoes (RBDPO-3). The deep-frying process was performed for 15 mins at 180 ± 5 °C for 15 cycles. Based on the results, the oil temperature fluctuation during the frying process was insignificant for every cycle (p > 0.05). After 15 frying cycles, all oil samples demonstrated a considerably altered and deteriorated composition, both physically and chemically. The comparison between the 1st and 15th frying cycles showed a significant difference (p < 0.05) in the decrease of moisture content and contact angle. Furthermore, the redness colour and viscosity for RBDPO-1, RBDPO-2 and RBDPO-3 increased significantly. The RBDPO-2 recorded the highest value for moisture content, contact angle, colour and viscosity after 15 frying cycles with 30.40 ± 0.2%, 26.01 ± 0.02°, 10.77 ± 0.15 Lovibond, and 133.5 ± 0.2 cP, respectively. However, the density value was insignificant (p > 0.05) between the 1st and 15th frying cycles for all types of oil. Besides, the peroxides value (PV) was steadily increased within the safety limit of Food Act (1983) (Laws of Malaysia: Act 281), with the aldehyde (CO) functional group was detected in all oil samples throughout the 15 frying cycles. Hence, the high correlation between the contact angle and all parameters except density showed that contact angle analysis using PLLA film was a suitable technique for rapid oil spoilage indicator model.     

Physicochemical features and antioxidant activity of polysaccharides from Herba Patriniae by gradient ethanol precipitation

Four polysaccharides BJP50, BJP60, BJP70 and BJP80 (total named BJPs) were separated from Herba Patriniae via gradient ethanol precipitation with 50%, 60%, 70% and 80%, respectively. After decolorization and deproteinization, their physicochemical features and antioxidant activities were investigated. The results showed that the total sugar content of BJPs accounted above 50% but no protein contained, while BJP50 and BJP60 contained a small amount of uronic acid. GC analysis indicated that BJPs were mainly composed of galactose, arabinose, glucose, mannose, xylose and rhamnose. From BJP50 to BJP80, the types of monosaccharides and the content of arabinose, glucose and mannose increased but that of galactose and rhamnose decreased, and their molecular weights gradually reduced from 2.3 × 10⁶ to 4.5 × 10³. BJPs had a good thermal stability with the order of BJP80 > BJP70 > BJP60 > BJP50. The vitro bioactivity assay showed that BJP80 and BJP70 exhibited stronger scavenging capacities for DPPH, ABTS and hydroxyl free radicals than that of BJP60 and BJP50. As the concentration reached 4 mg/mL, the scavenging capacities of BJP80 and BJP70 on DPPH and hydroxyl free radical were up to 92% and 95%, respectively, and their antioxidant activities gradually approached to the positive control.     

Effect of process production on antinutritional,nutrition, and physicochemical properties of modified sorghum flour

Increasing wheat flour consumption makes increasing of wheat import value in Indonesia. Wheat flour has good nutritions, sufficient gluten compound, high glucose and high glycemic index. Therefore, substituting wheat with sorghum (local crop) which has gluten free, a low glucose and glycemic index value, can overcome food security problem in Indonesia. However, it has a high phytic acid and tannin (antinutrients). This study focuses on the reduction of antinutrients by three processes (fermentation treatment using lactic acid bacterias (LAB), including Lactobacillus bulgaricuss, Lactobacillus casei, and Lactobacillus brevis (1); NaOH solution submersion (2); and combining NaOH solution submersion followed by fermentation (3)). It was found that combining NaOH solution submersion and fermentation resulted in reduction of antinutrient contents (phytic acid decreased from 11.9% to 0.117% and the tannin decreased from 6.16% to 0.063%) and improved nutrition composition (such as protein content increased from 8.59% to 14.67%) on sorghum so that sorghum could be feasible to be an alternative source of wheat substitution in flour production. Moreover, the glucose content and glycemic Index (GI) of modified sorghum flour was decreased from 2.75 to 1.83%, and decreased from 40.79 to 36.33, respectively.     

基于HPLC-RI与FAAS对云南春蜂蜜理化性质的研究

云南地区因其得天独厚的自然条件,具有丰富的蜜源植物和矿产资源,产出了多种特色蜂蜜。对该地区的三种特色春蜂蜜(苕子蜜、橡胶蜜和石榴蜜)进行了理化性质的研究,结果表明三种蜂蜜在水分含量、电导率和粘度上均存在显著性差异。利用高效液相色谱仪-示差折光检测器(HPLC-RI)测定三种蜂蜜中的主要糖类,结果显示石榴蜜中的葡萄糖含量最高[35.62 g·(100 g)-1],橡胶蜜中的果糖含量最高[41.03 g·(100 g)-1]。利用原子吸收光谱仪(FAAS)对三种蜂蜜中的13种矿质元素进行测定,结果显示橡胶蜜中的矿质元素总含量最高(437.34 mg·kg-1),石榴蜜中的最少(167.24 mg·kg-1)。将矿质元素作为变量进行主成分分析,可将三种蜂蜜相互分开。Cu,Zn和Na可作为苕子蜜的分辨标记,Mg,K,Ca,As和Cd可作为橡胶蜜的分辨标记,Fe,Mn,Ni和Cr可作为石榴蜜的分辨标记。本研究的开展可补充云南特色蜂蜜的研究,为其开发利用提供理论依据。     

化学改性琼脂糖凝胶的物化性能及其对重组人血白蛋白的纯化应用研究

考察了几种经过化学改性后带有离子交换配基的琼脂糖凝胶介质的理化性能.通过外形观察、元素及金属含量分析、柱效测定、耐压及流速测定、离子交换容量和蛋白吸附容量测定,从多方面对性能进行验证比较,并对其在分离纯化重组人血白蛋白的应用性能进行了初步研究.结果表明国产产品与进口产品理化性能相当.     

纳米HZSM-5沸石的骨架热稳定性及其作为催化剂的可再生性

采用高温焙烧和积炭失活-空气烧炭再生方法研究了纳米ZSM-5沸石的骨架热稳定性和用纳米HZSM-5沸石制成的芳构化催化剂的再生重复使用性能,还采用XRD、TG、FTIR、NH3-TPD和N2物理吸附,以及C4液化气固定床临氢芳构化反应对沸石和催化剂样品的物化性质作了表征.结果表明:纳米ZSM-5沸石具有良好的骨架热稳定性,在马弗炉的静止空气气氛中恒温焙烧800℃时仍可保持骨架结构.纳米HZSM-5型芳构化催化剂在C4液化气固定床临氢芳构化反应中不但活性稳定性好,而且可以再生重复使用,具有很高的工业应用价值.     

Physicochemical property based computational scheme for classifying DNA sequence elements of Saccharomyces cerevisiae

GenerationE of huge “omics” data necessitates the development and application of computational methods to annotate the data in terms of biological features. In the context of DNA sequence, it is important to unravel the hidden physicochemical signatures. For this purpose, we have considered various sequence elements such as promoter, ACS, LTRs, telomere, and retrotransposon of the model organism Saccharomyces cerevisiae. Contributions due to di-nucleotides play a major role in studying the DNA conformation profile. The physicochemical parameters used are hydrogen bonding energy, stacking energy and solvation energy per base pair. Our computational study shows that all sequence elements in this study have distinctive physicochemical signatures and the same can be exploited for prediction experiments. The order that we see in a DNA sequence is dictated by biological regions and hence, there exists role of dependency in the sequence makeup, keeping this in mind we are proposing two computational schemes (a) using a windowing block size procedure and (b) using di-nucleotide transitions. We obtained better discriminating profile when we analyzed the sequence data in windowing manner. In the second novel approach, we introduced the di-nucleotide transition probability matrix (DTPM) to study the hidden layer of information embedded in the sequences. DTPM has been used as weights for scanning and predictions. This proposed computational scheme incorporates the memory property which is more realistic to study the physicochemical properties embedded in DNA sequences. Our analysis shows that the DTPM scheme performs better than the existing method in this applied region. Characterization of these elements will be a key to genome editing applications and advanced machine learning approaches may also require such distinctive profiles as useful input features.