Effect of Gaseous Acetic Acid Treatment on Breadmaking Properties of Flour

Eleven different wheat flours of varying protein content were treated with gaseous acetic acid. Each wheat flour exhibited maximum breadmaking properties (bread height and specific volume) at different levels of gaseous acetic acid treatment. There was a relationship (r = +0.7384) between the level of gaseous acetic acid treatment required for maximum breadmaking properties and the protein content of the wheat flour. Wheat flours with higher protein contents were more resistant to the decrease in pH value due to acetic acid treatment.     

Effect of Gaseous Acetic Acid on Dough Rheological and Breadmaking Properties

Breads baked from wheat flours (protein contents 14.1–16.5% at 14.0% mb) that were pretreated with 2–3 mL of gaseous acetic acid per kg of wheat flour, showed maximum bread height and specific volume (cm³/g). Flour-water suspension and the crumb pH values were gradually decreased with increased amounts of acetic acid. Gas generation and dough expansion tests with bread dough showed that the addition of the same amount of acetic acid, which achieved maximum specific volume, also showed the highest rate of gas generation and dough expansion. However, increasing acetic acid decreased these values. Scanning electron microscope (Cryo-SEM) observation showed that the bread dough made from the same acetic acid-treated flour indicated continuum and no cracks in the dough matrix. Evaluation of mixograms showed the decrease of mixing stability with increased acetic acid levels. Viscosity and water binding capacity of flour-water suspensions were sharply increased by the addition of acetic acid at pH 5.0–3.5.     

Study of Three-Dimensional Structure of Wheat Starch Granules Stained with Remazolbrilliant Blue Dye and Extracted with Aqueous Sodium Dodecyl Sulfate and Mercaptoethanol Solution

Wheat starch granules were obtained from soft wheat flour by acetic acid fractionation (pH 3.5), and the starch was stained by reaction with Remazolbrilliant blue (RBB) dye. RBB-stained starch was extracted with 1% sodium dodecyl sulfate (SDS) and 1% 2-mercaptoethanol (ME) for 14.5 hr at room temperature. This extraction step was repeated five times (extracts 1–5). SDS-ME extracts were subjected to size-exclusion column chromatography, and comparisons of their profiles for specific absorbance at 650 nm (A₆₅₀) and carbohydrates were made. After high molecular weight (HMW) carbohydrates on the starch granule surface were extracted, HMW carbohydrates inside the granule appeared to be extracted. Finally, low molecular weight (LMW) carbohydrates near the granule surface were extracted. Phase-contrast light microscopy of the treated starch granules showed that all granules became transparent. Two different interior structures were observed. Scanning electron microscopy indicated that the granule was split into two parts at the equatorial groove. The interior of the granule showed two different areas: a central hole area and the surrounding stratified area. Extraction beyond five times with the same solvent dissolved the weak part of the granule structure and left two types of skeletal structures. The appearance of the skeletal structure of the granule surface was different from the appearance of interior structures.     

Changes in endogenous cytokinin-like substances and growth inhibitors in freesia corms during high-temperature treatment for breaking dormancy

High summer temperatures are required to break dormancy of freesia corms and cormels. Endogenous cytokinin levels were low in corms at the lifting-date, 25 May, but increased after 3 months storage at 30°C. Cytokinin levels in cormels increased gradually during summer storage at natural room temperature, reaching a maximum on 25 August when cormels had the capacity to sprout, then decreased to low levels on 25 September. Inhibitor levels in cormels decreased gradually during storage. A zeatin riboside-like compound, water-soluble cytokinins and an abscisic acid-like compound were present in freesia corms. Dormant corms, soaked for 18 h in 1000 mg/l benzyladenine solution, showed 100% sprouting. We conclude that high temperatures cause a decrease in inhibitors and an increase in cytokinins, which together result in the breaking of the dormant state of corms and cormels of freesia.     

Dietary utility of enzyme-treated fish meal for juvenile Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis>

ABSTRACT:   In order to develop an artificial diet, the dietary utility of enzyme-treated fish meal was investigated for juvenile Pacific bluefin tuna Thunnus orientalis (PBT). Diets containing each 63% of Chilean fish meal (FM), enzyme-treated Chilean fish meal (EC) and enzyme-treated Peruvian fish meal (EP), with 10% bonito oil and raw sand lance Ammodytes personatus (SL) were fed to juvenile tuna six times per day for one week. In a different trial, diets EC and SL were fed to tuna six times per day for 2 weeks. Only diet EC sustained similar growth or caused lower survival and higher feed efficiency, hepato- and enterosomatic indices and final carcass lipid content as compared to those of SL. Diets FM and EP led to lower specific growth rate (SGR) but similar feed efficiency, survival and hepatosomatic index, yet higher enterosomatic index. Moreover, PBT fed diet EC for 2 weeks led to similar growth performance but higher final carcass and hepatic lipid contents, and plasma cholesterol and phospholipid levels than those fed SL. Carcass fatty acid composition of diet EC group had lower 20:5  n -3 and 22:6  n -3 levels than the SL group. These results revealed that EC, as a suitable dietary protein source, could sustain growth of PBT, while dietary bonito oil led to higher carcass lipid but lower accumulation of n -3 highly unsaturated fatty acids.     

Genotypic Variation in Shoot Cadmium Concentration in Rice and Soybean in Soils with Different Levels of Cadmium Contamination

A pot experiment was conducted to investigate whether the shoot cadmium (Cd) concentration in 11 rice and 10 soybean cultivars varied among 4 soils with different levels of Cd contamination. Significant differences in shoot Cd concentration were found among rice or soybean cultivars grown in the 4 soils. The ranking of the rice cultivars for the shoot Cd concentration varied considerably among the soils. On the other hand, the soybean cultivars were ranked similarly in terms of shoot Cd concentration in the 4 soils. Significant and positive correlations were found between the Cd and Zn concentrations and between the Cd and Mn concentrations in the shoot of rice cultivars, when they were grown in 2 soils with relatively moderate levels of Cd contamination. The shoot Cd concentration in the soybean cultivars, however, was not correlated with the concentrations determined for any of the metals (Zn, Mn, Cu, and Fe) across the 4 soils. Significant and positive correlations between the concentrations of Cd in younger shoots and mature seeds were detected among the soybean cultivars in 2 soils used, unlike among the rice cultivars, indicating that it may be difficult to evaluate the genotypic variation in seed Cd concentration using relatively younger shoots in the case of rice. These results revealed that genotypic differences in shoot Cd concentration in rice or soybean are variable or invariable among soils, respectively.     

Response of pepper and eggplant to continuous light in relation to leaf chlorosis and activities of antioxidative enzymes

Activities of the oxygen radical-scavenging enzymes were determined in leaves of ‘Kyomidori’ pepper (Capsicum annuum L.) and ‘Senryo’ eggplant (Solanum melongena L.) seedlings under two photoperiod treatments; 12 h light/12 h dark (12/12 h) or with continuous light (24/0 h) for six days. Growing eggplant under continuous light resulted in leaf chlorosis after four days and a sharp decline in the chlorophyll content. In eggplants grown under 24/0 h photoperiod, the activities of antioxidative enzymes; superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) rapidly increased from day two. This was an indication of photooxidative damage. In contrast, leaf chlorosis did not occur in pepper plants grown under continuous light, while the chlorophyll content was even higher in the 24/0 h than in the 12/12 h photoperiod. Continuous light did not enhance the activities of SOD and POD in leaves of pepper. However, the CAT activity increased faster and was significantly higher in pepper than in eggplants grown under continuous illumination. Pepper plants did not appear to suffer from photooxidative damage and thus grew normally under continuous illumination.     

Ent-2'-epi-Orobanchol and its acetate, as germination stimulants for Striga gesnerioides seeds isolated from cowpea and red clover

Striga gesnerioides is a root parasitic weed of economic significance to cowpea (Vigna unguiculata) crops in Western Africa. Seeds of the parasite germinate in response to cowpea root exudates. Germination stimulants for the seeds were isolated from the hydroponic culture filtrate of cowpea, and their structures were unambiguously determined as (-)-(3aR,4R,8bR,2'R)-ent-2'-epi-orobanchol and (+)-(3aR,4R,8bR,2'R)-ent-2'-epi-orobanchyl acetate, on the basis of mass, CD, and (1)H NMR spectra; optical rotatory power; and chromatographic behavior on HPLC. The alcohol was first isolated and identified from the cowpea root exudates, and the acetate may be the same compound that had been previously isolated from the exudates and designated as alectrol. Identity of the stimulants produced by cowpea to those produced by red clover (Trifolium pratense) was confirmed.