Lectins, noncatalytic sugar-binding proteins of nonimmune origin, are widely distributed in the most common foods and feeds in varying amounts. Since many lectins, such as legume lectins, are relatively stable against heat denaturation and proteolytic digestion, the digestive tract is constantly exposed to biologically active lectins contained in fresh and processed foods. Lectins interact with the epithelial surface of the intestine and cause adverse effects, sometimes called food poisoning, in humans and animals. Meanwhile, many interesting biological functions have been discovered in lectins originating from foods or foodstuffs, including immunomodulating effects, selective cytotoxicity against cancer cells, antimicrobial and insecticidal activities, modulating effect on the intestinal transport system, and so on. This review aims to present the current state of research on lectins as bioactive proteins in foods and feeds in order to provide opportunities for application development.
L-alanine is an important amino acid that constitutes proteins and provides biological advantages to the human body. This study examined conditions for the crystallization of L-alanine using liquid anti-solvents and ultrasound as an auxiliary tool. Effects of process variables on the distribution of particle size and external habit were investigated. Propanol was found to be the most appropriate anti-solvent. In addition, results of particle size analyzer and scanning electron microscope revealed that the particle size of L-alanine crystals increased with an increase in L-alanine concentration, injection rate, or crystallization temperature. Ultrasound also caused significant particle size reduction.
The objective of this study was to analyze the surface oil ratio and distribution measurement of spray-dried powders during hexane washing, in order to evaluate the properties of fish oil-encapsulated powders. Two types of spray-dried powders were prepared from two differently sized emulsions, namely: (i) nano and (ii) microsized oil droplets. A matrix composed of maltodextrin and sodium caseinate was used as the wall material to encapsulate the fish oil, and Nile red was used to stain the oil. The extraction of the surface oil releases a threshold amount of oil on the surface of the particle. The study of the fluorescence intensity using confocal laser scanning microscopy (CLSM) indicates good correlation between the oil content and fluorescence intensity. It was difficult to remove the surface oil of the nano-sized oil droplets in the spray-dried powders by hexane washing because the smaller oil droplets had higher stability in the spray-dried powders.
The contents of 6 kinds of heavy metals (Pb, Cr, Cd, As, Cu, Ni) in moso bamboo shoot were measured by inductively coupled plasma-mass spectroscopy (ICP-MS). The health risk of the 6 kinds of heavy metals was assessed by the target hazard quotients (THQ). The mean contents of Pb, Cr, Cd, As, Cu and Ni in all analyzed bamboo shoots were 6.19 ∼ 92.8, 1.38 ∼ 137, 1.22 ∼ 35.5, 1.14 ∼ 7.48, 224 ∼ 1266 and 31.4 ∼ 381 µg kg−1, respectively. The contents of these heavy metals in all samples were below the corresponding maximum limits established by Ministry of Health P. R China. It is observed that each heavy metal THQ value was below 1.0. The TTHQs of the heavy metals for adults and children were 0.116 ∼ 0.152 and 0.165 ∼ 0.216, the results indicate that the ingestion of moso bamboo shoots will not bring risks to residents.
Lysophosphatidic acid has a role in protecting the gastrointestinal tract, and is formed from the digestion of exogenous foodstuff-derived phosphatidic acid (PA) in the human digestive tract. Japanese mustard spinach (Komatsuna) is an important source of foodstuff-derived PA. PA does not accumulate at high levels in Komatsuna, but is abundantly released upon grinding of Komatsuna. To manufacture PA-rich food using Komatsuna, the characteristics of micro wet milling (MWM) and PA production of Komatsuna were investigated. The results show that after grinding, PA was found at sufficient levels in Komatsuna, and MWM could effectively decrease the particle size as well as release PA. As the particle size of Komatsuna tissues decreased, the measured amount of PA increased. This phenomenon can be explained by the high proportion of native Komatsuna PA released from the biomembrane due to particle disruption, and possibly by the release of endogenous phosphatidylcholine during grinding, which is then converted to PA by phospholipase D.
In recent years, phytosterols and their fatty acid esters have attracted much attention due to their beneficial effects on human health, while the latter showed excellent advantage in oil solubility. In this study, a novel method was developed for highly efficient synthesis of phytosterol linolenate through lipase-catalyzed transesterification of phytosterols with ethyl linolenate. The effects of lipase, and of solvents with different Log P values on the transesterification of phytosterols were investigated. And the solubility of phytosterols and residual activities of lipase after exposure to different solvents were also considered. Results showed that the conversion was positive correlated with the Log P values of the solvent. Candida rugosa lipase and iso-octane was the most suitable biocatalyst and solvent, respectively. The effects of other reaction parameters, including lipase load, reaction temperature, substrate concentration, substrate molar ratio and reaction time on the conversion of phytosterols to phytosterol linolenate were investigated. And the highest yield (95.9 ± 0.8%) of phytosterol linolenate was obtained in short reaction time (2 h) under the selected conditions: 75 mmol/L phytosterols, 1:1.75 molar ratio of phytosterols to ethyl linoenate, 120 g/L 3 Å molecular sieves and 20 g/L Candida rugosa lipase in iso-octane, 150 r/min and 40°C, suggesting that Candida rugosa lipase–catalyzed transesterification of phytosterols was an efficient route for phytosterols esters synthesis. The solubility of phytosterols and its linolenate in vegetable oil was also compared and results showed that the oil solubility of phytosterols was significantly improved by transesterification with ethyl linolenate, facilitating the incorporation into a variety of oil- or fat-based foods.
Ultrasound assisted extraction (UAE) was used to extract phenolic compounds and anthocyanins from perilla leaves. Response surface methodology (RSM) was used to optimize the extraction conditions. The optimal conditions were as follows: ethanol concentration of 76.58%, liquid-to-solid ratio of 22.15:1, extraction temperature of 52.75°C and extraction time of 53.84 min. Under these optimal conditions, total phenolic content (TPC) and the total anthocyanins content (TAC) were 63.11 mg gallic acid equivalent (GAE)/g dry weight (DW) and 6.44 mg cyanidin-3-glucoside equivalent (CGE)/g DW, respectively. The experimental data are consistent with the predicted values, confirming that the model was valid for optimization of the extraction conditions. In addition, perilla extract was purified using XAD-7 resin. The antioxidant activity of purified extract was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-ethyl-benzo-thiazoline-6-sulphonate (ABTS) methods (50% inhibition values of 19.88 µg/mL by DPPH and 81.75 µg/mL by ABTS). The results indicated that purified extract exhibited potent antioxidant capacity.
The severity of internal browning in apple cultivars is often evaluated subjectively, making it potentially unreliable, and a method for automatic evaluation is necessary in order to process many samples efficiently. The objective of this study was to propose a model for estimating subjective browning severity ratings (SBSRs) in scanned images of sliced apples that mimics mean expert judgments. We assessed SBSRs made by three expert observers for images of sliced apples. The results indicated that the experts' evaluations of internal browning were qualitatively similar, but not quantitatively equivalent. The proposed model estimates the mean SBSRs of experts as a percentage of the browning region of the total flesh. The browning regions were qualified using CIELAB color difference from the standard color. The model estimations were consistent with increasing browning during longer storage periods.
Tamarind seed polysaccharide (TSP) belongs to the galactoxyloglucan family and is used as a thickener or stabilizer in the food industry. To establish a quantitative method for TSP, the iodine-staining method was implemented and validated using various marketed TSP products in terms of selectivity, linearity, range, trueness, precision, and uncertainty. Good linearity was confirmed for the TSP reference standard (RS) over the concentration range of 5 – 449 µg/g. The tested method yielded good recovery from the spiked test (99 – 107%) and precision using RS and various marketed TSP products (repeatability precision (RSDr): 1.0 – 1.9%, intermediate precision (RSDi): 1.5 – 3.5%), suggesting the validity of the quantitative method. The quantitative method was applicable to currently marketed TSP products. We conclude that this method is a simple and practical method with high trueness and precision for the determination of TSP concentration to certify marketed TSP products as food additives.
The inactivation effect of carbonation under heating (CH) followed by heating (HT2) in the presence of monoglycerol monocaprate (MC10) or monoglycerol monolaurate (MC12) on Bacillus subtilis spores was investigated. CH (80°C, 5 MPa, 10 min) followed by HT2 (90°C, 10 min) induced an approximately 5 log order of inactivation in the presence of MC10 or MC12 at 0.05% (w/v). MC12 appeared to have a greater effect on increasing the inactivation effect of CH followed by HT2 than MC10. Heating, pressurization, and pH downshift involved in CH may play important roles in the high inactivation effect of CH followed by HT2. As indicated by increased DAPI stainability, CH in the presence of MC10 forced germination. The results show that heating after CH in the presence of MC10 and MC12 effectively inactivated B. subtilis spores under milder heating conditions than conventional autoclaving.
Solid lipid nanoparticle (SLN) could be adopted as a potential nanovehicle for improving iron absorption. The rat everted intestinal sac model was employed to investigate the absorption of ferrous glycinate SLNs, to evaluate the resistance of the SLNs against phytic acid and zinc, and to estimate the effect of the SLN particle sizes on iron absorption. The results showed that the iron absorption was obviously enhanced after ferrous glycinate incorporation into SLNs. The inhibitory effects of phytic acid and zinc on iron absorption could be partly prevented by SLNs, and meanwhile the iron absorption could be improved. Furthermore, the results indicated that the relationship between ferrous glycinate SLNs and iron absorption was size-dependent, and the absorption increased with decreasing of SLN particle sizes. The results suggested that the SLNs could alter the absorption pathways of iron besides simple carriers. SLN could be an effective carrier to improve the absorption of nonheme iron.
We investigated the anti-allergic activities of a hot water extract of Stephania tetrandra S. Moore using RBL-2H3 cells and an allergic rhinitis mouse model. The degranulation levels were significantly lower in the water-solvent fraction (WEx) and 99% ethanol fraction (99% EtEx) extracted from S. tetrandra than in the control. However, the cell viability of 99% EtEx was significantly lower than the control. In an ovalbumin allergic rhinitis mouse model, the frequency of sneezing after the fifth nasal ovalbumin (OVA) challenge in the groups intragastrically administered WEx and 99% EtEx decreased significantly compared to the control, although this decrease was lost following the sixth or seventh challenge. Plasma levels of OVA-specific immunoglobulin E in the WEx and 99% EtEx groups were significantly lower than the control at the experimental end point. Thus, S. tetrandra was proposed to be an effective anti-allergic natural medicine.
The volatiles of Bacillus subtilis CF-3 showed a significant ( p < 0.05) suppression of the mycelial growth of Monilinia fracticola and Colletotrichum gloeosporioides which caused postharvest decay of Peach and Litchi. An 85-µm polyacrylate (PA) extraction fiber was initially selected used for the optimized experiments. For an optimal CF-3 volatile collection, HS-SPME was suggested to be performed with extraction time of 40.8 min and extraction temperature of 38.5°C and with 41.5 mL LB broth medium and 4.15 mL CF-3 fermentation liquor (1×108 CFU/mL) based on the response surface methodology (RSM). 61 volatile compounds, including fourteen alcohols, fifteen ketones, two aldehydes, eight acids, five phenols, three pyrazines, four esters, three olefins, two amines, two ethers, etc., were extracted using three types of fibers by the optimum method with similarity index (SI)>850 from the database search. Good predictability of the model, satisfactory repeatability for all volatile compounds according to the optimized HS-SPME conditions indicated that the HS-SPME procedure was applicable for the analysis of volatile release, six compounds were selected and assayed for antifungal activity in divided Petri plates, 1-Octanol and 2,4-Di-tert-butylthiophenol can inhibit the mycelial growth of M. fracticola and C. gloeosporioides, which will aid in further research on bio-bacterium volatile metabolites as biocontrol agents against postharvest diseases in fruits and vegetables.
Effects of pH on the physical properties of heat-induced whey protein aggregates were investigated using atomic force microscopy. At pH 5.5 and a protein concentration of 0.3% (w/w), micrometer-sized aggregates were formed within 1 min of heating at 80°C, while it took more than 30 min for aggregates to reach similar sizes at pH 7.0 and a protein concentration of 2.0% (w/w). The surface roughness of air-dried aggregates evaluated based on cross-sectional height data decreased by a factor of 2 with increasing pH from 5.5 to 7.0. Young's modulus values of whey protein aggregates evaluated based on force-indentation curve measurements without drying decreased by a factor of 3 with increasing pH from 5.5 to 7.0. The present results suggest that heat-induced whey protein aggregates became mechanically weaker with increasing pH due to increased inter-/intra-molecular electrostatic repulsions.
Bananas (Musa spp.) are not only one of the most popular fruits but also important staple food in some tropic countries. Carotenoid in pulp of banana fruits is an important source of vitamin A. While little is reported on carotenoid in peel, which is traditionally recognized as byproduct of food industry and may be a potential source of antioxidant compounds. Here we determined and reported carotenoid content and composition in both peel and pulp of 36 different banana cultivars. A total of 3 and 8 carotenoid components were identified in pulp and peel, respectively. The results show that carotenoid ranged from 0.18 to 36.82 µg/g FW in pulp and 0.9 to 16.2 µg/g FW in peel. Vitamin A values as retinol activity equivalents (RAE) in the pulp ranged from 0.003 to 1.85 µg/g. This report represents the first comprehensive assessment of carotenoid profiling in both fruit peel and pulp of 36 white to orange types of bananas and demonstrates banana peel product is also a valuable source with great nutritional properties.
Through the use of on-line atmospheric pressure photoionization quadrupole time-of-flight mass spectrometry (APPI-QTOFMS), 32 volatiles from garlic were tentatively identified, and 9 metabolites were observed in exhaled breath after garlic ingestion. Methional and 3-methylthiopropionic acid, which may reflect the metabolism of methionine from garlic, were observed in garlic breath for the first time. Variation of metabolites was also monitored within 1 h to show the metabolic processes. The signal intensity of methional, 3-methylthiopropionic acid and p-cymene was increased within 35 min and then declined. Other 6 metabolites including allyl mercaptan, allyl methyl sulfide, diallyl sulfide, allyl methyl disulfide, diallyl disulfide and dimethyl selenide reached maxima shortly after ingestion of garlic and declined continuously. Our result indicates that APPI-QTOFMS is potential for investigation of food metabolism in dynamic via exhaled breath.
Cooking rice mixed with barley, called Mugimeshi in Japanese, is one of the most common multi-grain cooking styles in Japan. While the localization and functions of rice starch-degrading enzymes such as α- and β-amylases during rice cooking have been well studied, those of barley enzymes remain unknown—especially when barley is cooked with rice. In this study, we investigated the localization of barley β-amylase using an immunoblot technique when barley and rice were soaked in water and heated together to 60°C. Surprisingly, barley β-amylase was found not only in barley grains and cooking water, but also in rice grains after barley and rice were soaked in water for one hour. In rice grains, the amount of barley β-amylase was highest when the water temperature reached 40°C. These data clearly showed that some barley β-amylase was translocated from barley grains into rice grains through the cooking water. The finding raises the possibility that in addition to rice enzymes, barley β-amylase contributes to rice starch degradation during Mugimeshi cooking.