Preparation,Bioavailability, and Mechanism of Emerging Activities of Ile‐Pro‐Pro and Val‐Pro‐Pro

Ile‐Pro‐Pro and Val‐Pro‐Pro are two most well‐known food‐derived bioactive peptides, initially identified as inhibitors of angiotensin I‐converting enzyme (ACE) from a sample of sour milk. These two peptides were identified in fermented and enzymatic hydrolyzed cow and non‐cow (that is, goat, sheep, buffalo, yak, camel, mare, and donkey) milk, as well as sourdough prepared from wheat, rye, and malt. Similar to other bioactive peptides, bioavailability of these peptides is low (about 0.1%), reaching picomolar concentration in human plasma; they showed blood pressure lowering activity in animals and in human, via improved endothelial function, activation of ACE2, and anti‐inflammatory property. Emerging bioactivities of these two peptides toward against metabolic syndrome and bone‐protection received limited attention, but may open up new applications of these peptides as functional food ingredients. Further studies are warranted to determine the best source as well as to identify novel enzymes (particularly from traditional fermented milk products) to improve the efficiency of production, to characterize possible peptide receptors using a combination of omics technology with molecular methods to understand if these two peptides act as signal‐like molecules, to improve their bioavailability, and to explore new applications based on emerging bioactivities.     

Application of Sensory Evaluation,HS‐SPME GC‐MS,E‐Nose,and E‐Tongue for Quality Detection in Citrus Fruits

In this study, electronic tongue (E‐tongue), headspace solid‐phase microextraction gas chromatography‐mass spectrometer (GC‐MS), electronic nose (E‐nose), and quantitative describe analysis (QDA) were applied to describe the 2 types of citrus fruits (Satsuma mandarins [Citrus unshiu Marc.] and sweet oranges [Citrus sinensis {L.} Osbeck]) and their mixing juices systematically and comprehensively. As some aroma components or some flavor molecules interacted with the whole juice matrix, the changes of most components in the fruit juice were not in proportion to the mixing ratio of the 2 citrus fruits. The potential correlations among the signals of E‐tongue and E‐nose, volatile components, and sensory attributes were analyzed by using analysis of variance partial least squares regression. The result showed that the variables from the sensor signals (E‐tongue system and E‐nose system) had significant and positive (or negative) correlations to the most variables of volatile components (GC‐MS) and sensory attributes (QDA). The simultaneous utilization of E‐tongue and E‐nose obtained a perfect classification result with 100% accuracy rate based on linear discriminant analysis and also attained a satisfying prediction with high coefficient association for the sensory attributes (R² > 0.994 for training sets and R² > 0.983 for testing sets) and for the volatile components (R² > 0.992 for training sets and R² > 0.990 for testing sets) based on random forest. Being easy‐to‐use, cost‐effective, robust, and capable of providing a fast analysis procedure, E‐nose and E‐tongue could be used as an alternative detection system to traditional analysis methods, such as GC‐MS and sensory evaluation by human panel in the fruit industry.     

Moisture‐Absorption and Water Dynamics in the Powder of Egg Albumen Peptide,Met‐Pro‐Asp‐Ala‐His‐Leu

Moisture absorbed into the powder of Met‐Pro‐Asp‐Ala‐His‐Leu (MPDAHL)—a novel egg albumen antioxidant peptide—profoundly affects its properties. In this study, we elucidated water dynamics in MPDAHL using DVS, DSC, and low‐field ¹H NMR. Based on the DVS data, we found that MPDAHL sorption kinetics obey a parallel exponential model. DSC results indicated that both water and heating could change the microstructure of MPDAHL. The T₂ parameters of NMR reflected the different phases of moisture absorption revealed that there were 4 categories of water with different states or mobility in the MPDAHL during the moisture absorption process. The fastest fraction T_2b mainly dominated the hygroscopicity of MPDAHL and the absorbed water significantly changed the proton distribution and structure of MPDAHL. Thus, this study shows that DVS, DSC, and low‐field ¹H NMR are effective methods for monitoring water mobility and distribution in synthetic peptides. It can be used to improve the quality assurance of functional peptides.     

Absorption and twenty‐four‐hour metabolism time‐course of quercetin‐3‐O‐glucoside in rats,in vivo

Rats were meal‐fed a semi‐synthetic diet, with or without quercetin 3‐O‐glucoside (Q3G; 100 mg per meal) and groups of three were killed either fasting, or at 2, 5 and 24 post‐feeding. Flavonoids and their metabolites in the diet, stomach contents, small intestinal lumen and mucosa, caecal contents and plasma were determined by LC/MS. Q3G was not hydrolysed in the stomach, but deglycosylation and further metabolism occurred in the small intestinal mucosa. At least 17 flavonoid glucuronides were identified in the lumen and mucosa, with evidence of time‐dependent changes such as de‐ and re‐glucuronidation. Quercetin mono‐sulphate was also detected in the small intestinal contents. Metabolites were still present in tissue and plasma 24 h after feeding. There was also evidence of complex microbial processing of Q3G in the caecal lumen with the appearance of at least one methylquercetin‐mono‐glucuronide, mono‐sulphate unique to this site in the gut, together with phenolic acid derivatives. Intestinal flavonoid metabolism is thus a very complex process in mammals, involving both enterocytes and bacteria. Copyright © 2004 Society of Chemical Industry     

Chapter 3: Double‐Embryo,High‐Protein,High‐Oil Maize Produced Using a Cytokinin‐Based Flower Rescue

ABSTRACT: Maize is an important staple of human diets and animal feed.Improving the nutritional profile for both of these purposes is a desirable research focus and agricultural endpoint. Many mechanisms have been used to improve maize protein and oil content, including selective breeding to introgress desirable traits (Quality Protein Maize), introducing single natural or synthetic genes expressing desired traits, changing signal sequences (high methionine maize), and modifying metabolic pathways (high‐lysine maize, see Chapter 6). A novel approach was used to indirectly increase protein and oil content ( Young and others 2004 ). Maize produces unisexual florets. Within the maize spikelet,the meristem gives rise to an upper and lower floret and male (tassel)‐ and female (ear)‐specific florets are borne on separate inflorescences.The lower floret of each ear spikelet is aborted early in its devel‐opment,leaving the upper floret to mature as the only female floret.Expression of a bacterial cytokinin‐synthesizing isopentenyl transferase (IPT) enzyme,under the control of the Arabidopsis senescence‐inducible promoter SAG 12 (senescence associated gene), blocked the abortion of the lower floret and resulted in 2 functional florets per spikelet.The pistil in each floret was fertile,but the spikelet produced just 1 kernel composed of a fused endosperm with 2 viable embryos.The 2 embryos were genetically distinct, indicating that they had arisen from independent fertilization events. The embryo contains most of the protein and oil in the kernel and kernels that contained 2 embryos have more protein than conventional maize.The presence of 2 embryos in a normal‐sized kernel leads to displacement of endosperm growth, resulting in kernels with an increased ratio of embryo to endosperm content. The end result is maize with more protein and oil and less carbohydrate ( Young and others 2004 ).     

The Interaction Between Surfactants and 2‐Hydroxy‐3‐(N,N‐dimethyl‐N‐dodecylammonium)‐propyloxy Starches

The phase behavior of temperature‐responsive hydrophobically modified starches and the interaction between oxidized potato amylose and hydrophobically modified potato amylopectin have been investigated by rheology, turbidity measurements and differential scanning calorimetry. When oxidized amylose was mixed with hydrophobically modified amylopectin, a viscosity peak was observed, indicative of a guest‐host interaction between the oxidized amylose and the hydrophobically modified amylopectin. A series of oxidized and hydrophobically modified potato starches were investigated in the presence of an anionic and cationic surfactant. A coil‐helix transition of the investigated starches was observed in the presence of surfactant, with the exception of a cationic surfactant combined with a hydrophobically modified zwitterionic starch of high positive net charge. The destabilizing mechanism (the phase separation) of the hydrophobically modified starches was studied as well as the difference in stabilizing capacity between the investigated cationic and anionic surfactants.     

The Sweetness Concentration‐Response of R,R‐Monatin,a Naturally Occurring High‐Potency Sweetener

Abstract: Monatin, known by the common and usual name arruva, is a zero‐calorie, high‐potency sweetener naturally occurring in the plant Sclerochiton ilicifolius A.Meeuse. The sweetness concentration‐response (C‐R) behavior of the most potent isomer (R,R‐) in room‐temperature (21 °C) water was determined using two‐alternative forced choice discrimination tests with a minimum of 69 tasters. Results were processed by a method previously published to obtain isosweet concentrations of sucrose for 8 monatin concentrations up to 240 mg/L. These were used to construct a C‐R plot. The equation for the resultant hyperbolic curve relating sucrose equivalent (SE,%) to monatin concentration ([monatin], mg/L) was SE = 26.7 ×[monatin]/(69.6 +[monatin]). R,R‐monatin has a potency above 3000 at 5% sucrose equivalent, making it one of the most potently sweet naturally occurring substances known. Practical Application: Monatin is a naturally occurring, zero‐calorie, high‐potency sweetener. We have measured the sweetness of monatin over a range of concentrations. This information will help developers of zero‐, low‐ and reduced‐calorie products formulate with monatin.     

Phase and Gelation Behavior of 2‐Hydroxy‐3‐(N,N‐dimethyl‐N‐dodecylammonium)propyloxy Starches

Some starches containing quaternary dimethylalkylammonium groups exhibit an unique phase behavior. A solid phase or gel phase is formed upon cooling, i.e. they are temperature‐responsive polymers. The aim of this study was to investigate the phase and gelation behavior of hydrophobically modified quaternary ammonium starch ethers in aqueous solutions. The mechanisms behind the phase behavior and hydrophobic character were investigated by light scattering (turbidity) and rheological measurements. A relatively large increase in the complex viscosity at higher concentrations was observed when the solutions were cooled to room temperature. The phase angle decreased drastically at a certain critical temperature. The decrease in the phase angle depended on the concentration of starch in solution, higher concentrations showing the greatest decrease and lower concentrations showing no significant change. Turbidity measurements indicated that a solid‐like highly concentrated phase was precipitated. The starch with zero net charge showed a larger increase in turbidity than the starch with a positive net charge, which indicates that particular precipitation is favored by a zero net charge and that the formation of a gel network is favored by charged starch molecules.     

Preparation,characterization, and water resistance of cationic acetylated starch‐g‐poly(styrene‐butyl acrylate) surfactant‐free emulsion

Cationic acetylated starch‐g‐poly(styrene‐butyl acrylate) surfactant‐free emulsion (CAS‐g‐poly(St‐BA)) was synthesized by graft copolymerization of styrene (St) and butyl acrylate (BA) onto CAS using FeSO₄–H₂O₂ redox initiator. The maximum graft of 55.68% was derived when H₂O₂ concentration, monomer concentration, and St/BA ratio were 9%, 130%, and 1:1, respectively. The results obtained from FTIR, NMR (H¹ NMR and C¹³ NMR), XRD, SEM, and thermogravimetric analysis (TGA‐DTG) confirmed graft copolymerization of St and BA onto CAS. And it was demonstrated that film‐forming properties of starch were greatly improved via grafting St and BA onto starch. It was also found that paper sized with CAS‐g‐poly(St‐BA) exhibited higher ring crush index and bursting strength than paper sized with cationic potato starch (CS) and CAS, as well as much lower water absorption, which is further verified by contact angles results.