Reproductive morphology in Mediterranean Seirospora giraudyi (Ceramiales, Rhodophyta)

This paper presents a detailed description of the reproductive characters of Mediterranean Seirospora giraudyi based on fresh material collected in the northwestern coast of Spain. Vegetative cells are uninucleate. The plant is monoecious. Spermantangial parent’s cells are clustered on modified dwarf determinate filaments, usually situated on adaxial surfaces of branches. One to four spermatia are formed by elongation and proximal divisions of the spermatangial parent cells. Spermatium with a nucleus situated ina mec. The thallus is procarpic. The four-celled carpogonial branch is initially L-shaped, and it is situated on a periaxial supporting fertile axial cell. The mature carpogonial branch is U-shaped and the supporting cell and second periaxial cell enlarge and divide transversely to reproduce a pair uninicleate auxiliary cell. The nucleus in the ferlilized carpogonium divides twice and the carpogonium cleaves vertically into two cells that, turn, cut off a pair of uninucleate connecting cells that fuse with the auxiliary cells on opposite sides; the diploid nuclei in the connecting cells divide at the site of fusion and one of the nuclei enters the auxiliary cell white the other is extruded. Each auxiliary cell gives to a terminal primary gonimolobe initials. Gonimolobes form lax chains of carposporangia. As the gonimoblasts mature, both lobes of the foot cell which is situated on the supporting cell elongate the upper one secondary connecting with the supporting cell, and the lower one with the fertile axial cell. The gonimoblasts are subtended at maturity by one to several clusters of involucral flaments. Seirospora is currently placed in the tribe Euptiloteae; however the reproductive character of S.giraudyi is dentical to those described for the Cañllithamnieae. Molecular studies are needed to confirm the taxonomic position of S.giraudyi as well as that of the other species placed Seirospora

Modificação química e física do amido de quirera de arroz para aproveitamento na indústria de alimentos

The study evaluated the efficiency of chemical (phosphorylation) and physical (extrusion) modifications of the starch of broken rice. Results demonstrated a reduction in the moisture content of extruded and phosphorylated broken rice and an increase in the ash content of phosphorylated broken rice. Both phosphorylation and extrusion increased cold water binding capacity, swelling power, and solubility. Extruded and phosphorylated pastes were stable under refrigeration, but only extruded paste was stable when submitted to freezing. Phosphorylated paste had the lowest viscosity and the highest stability during heating, while the extruded one gelatinized without heating, but had higher losses during heating.

Volatile compounds in the thermoplastic extrusion of bovine rumen

The volatile compounds of raw and extruded bovine rumen, extracted by dynamic headspace, were separated by gas chromatography and analyzed by GC-MS. Raw and extruded materials presented thirty-two volatile compounds. The following compounds were identified in raw bovine rumen: heptane, 1-heptene, 4-methyl-2-pentanone, toluene, hexanal, ethyl butyrate, o-xylene, m-xylene, p-xylene, heptanal, limonene, nonanal, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane and octadecane. The following compounds were identified in the extruded material: 1-heptene, 2,4-dimethylhexane, toluene, limonene, undecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane and nonadecane. Mass spectra of some unidentified compounds indicated the presence of hydrocarbons with branched chains or cyclic structure.

Pituussuunnassa hitsatun rakenneputken väsymislujuus HF –hitsausta käytettäessä

Tässä diplomityössä määritettiin pituussuunnassa hitsatun rakenneputken väsymislujuus HF –hitsausta käytettäessä. Työn tavoitteena oli vertailla eri jälkikäsittelyjen ja kahden eri materiaalin vaikutusta väsymislujuuteen. Materiaaleina kokeissa oli Ruukki double grade ja Optim 700 Plus MH. Eurokoodi 3 ja IIW määrittelee kiinnityshitseille väsymiskestävyysluokaksi 125-140, kun SN -käyrän kaltevuus, m = 3. Koetuloksia vertailtiin näihin valmiiksi määriteltyihin väsymiskestävyysluokkiin. Ruukki Metals Oy toimitti koemateriaalin kahdenlaisia väsytyskokeita varten, joiden avulla väsymislujuus voitiin määrittää. Ensimmäinen koe suoritettiin värähtelyllä hyödyntäen rakenneputken ominaistaajuutta, jolloin kuormituksen rajajännityssuhde on -1. Toinen väsytyskoe suoritettiin rakenneputkista leikatuille väsytyssauvoille, missä pituussuuntainen HF –hitsi on keskellä sauvaa. Tämä väsytyskoe suoritettiin vetotykytyksellä rajajännityssuhteella 0,1. Väsytyskokeissa havaittiin, että kiinnityshitsi täyttää sille asetetut vaatimukset, koska murtumat tapahtuivat perusaineesta. Tällöin koetuloksia vertaillaan Eurokoodi 3:n perusaineen väsymisluokkaan 160, SN -käyrän kaltevuudella m = 5. Kaikkien koetulosten väsymiskestävyysluokan keskiarvoksi saatiin 185 95 %:n todennäköisyydellä. Tutkimuksessa saatiin arvokasta tietoa kahden eri materiaalin väsymislujuudesta. Materiaalilla ei kuitenkaan havaittu vaikutusta lujuuteen. Eri jälkikäsittelyt eli juuren puolen metallipurseen höyläys tai pituussuuntaisen hitsisauman hehkutus eivät vaikuttaneet väsymislujuuteen. Kokeissa väsymismurtuma ydintyi rakenneputken pinnalta olevista alkuvioista, joten putkien käsittelyä valmistuksen jälkeen voitaisiin parantaa.

Egg size, yolk mass extrusion and hatching behavior in two cryptic speciesof Anastrepha fraterculus (Wiedemann) (Diptera, Tephritidae)

Variations in egg length were observed for two populations of cryptic species of Anastrepha fraterculus (Wiedemann). The eggs of type I flies were smaller than those of type II individuals. For both types, in regard to yolk mass extrusion, four classes of embryos were detected. Class 1: embryos that extrude masses at both extremities; class 2: embryos in which extrusion occurs only at the anterior pole; class 3: embryos that eliminate mass only at the posterior pole, and class 4: embryos that do not extrude any mass. Embryo class frequencies were similar for populations belonging to the same type, but different between types. Individual females may produce eggs from different embryo classes, but for any given female the pattern remains constant during a long period of oviposition. Variation in size of the extruded masses was similar for both populations. Individual females produced embryos with a small range of mass diameters, and different females produced masses of different mean size. However, individual mass size remained constant during oviposition. The results suggest the existence of genetic components involved in the control of this unusual process. Larvae of both types presented, just before eclosion, similar unusual behaviors: they ingest the anterior extruded mass, rotate 180°, absorb the posterior mass and eclose near the posterior pole. Data show that cryptic A. fraterculus type I and type II differs in regard to egg size as well as to the phenomenon of yolk mass extrusion

Modification of commercial poly-lactide for extrusion coated food packaging applications

Poly-L-lactide (PLLA) is a widely used sustainable and biodegradable alternative to replace synthetic non-degradable plastic materials in the packaging industry. Conversely, its processing properties are not always optimal, e.g. insufficient melt strength at higher temperatures (necessary in extrusion coating processes). This thesis reports on research to improve properties of commercial PLLA grade (3051D from NatureWorks), to satisfy and extend end-use applications, such as food packaging by blending with modified PLLA. Adjustment of the processability by chain branching of commercial poly-L-lactide initiated by peroxide was evaluated. Several well-defined branched structures with four arms (sPLLA) were synthesized using pentaerythritol as a tetra-functional initiator. Finally, several block copolymers consisting of polyethylene glycol and PLLA (i.e. PEGLA) were produced to obtain a well extruded material with improved heat sealing properties. Reactive extrusion of poly-L-lactide was carried out in the presence of 0.1, 0.3 and 0.5 wt% of various peroxides [tert-butyl-peroxybenzoate (TBPB), 2,5-dimethyl-2,5-(tert-butylperoxy)-hexane (Lupersol 101; LOL1) and benzoyl peroxide (BPO)] at 190C. The peroxide-treated PLLAs showed increased complex viscosity and storage modulus at lower frequencies, indicating the formation of branched/cross linked architectures. The material property changes were dependent on the peroxide, and the used peroxide concentration. Gel fraction analysis showed that the peroxides, afforded different gel contents, and especially 0.5 wt% peroxide, produced both an extremely high molar mass, and a cross linked structure, not perhaps well suited for e.g. further use in a blending step. The thermal behavior was somewhat unexpected as the materials prepared with 0.5 wt% peroxide showed the highest ability for crystallization and cold crystallization, despite substantial cross linking. The peroxide-modified PLLA, i.e. PLLA melt extruded with 0.3 wt% of TBPB and LOL1 and 0.5 wt% BPO was added to linear PLLA in ratios of 5, 15 and 30 wt%. All blends showed increased zero shear viscosity, elastic nature (storage modulus) and shear sensitivity. All blends remained amorphous, though the ability of annealing was improved slightly. Extrusion coating on paperboard was conducted with PLLA, and peroxide-modified PLLA blends (90:10). All blends were processable, but only PLLA with 0.3 wt% of LOL1 afforded a smooth high quality surface with improved line speed. Adhesion levels between fiber and plastic, as well as heat seal performance were marginally reduced compared with pure 3051D. The water vapor transmission measurements (WVTR) of the blends containing LOL1 showed acceptable levels, only slightly lower than for comparable PLLA 3051D. A series of four-arm star-shaped poly-L-lactide (sPLLA) with different branch length was synthesized by ring opening polymerization (ROP) of L-lactide using pentaerythritol as initiator and stannous octoate as catalyst. The star-shaped polymers were further blended with its linear resin and studied for their melt flow and thermal properties. Blends containing 30 wt% of sPLLA with low molecular weight (30 wt%; Mwtotal: 2500 g mol-1 and 15000 g mol-1) showed lower zero shear viscosity and significantly increased shear thinning, while at the same time slightly increased crystallization of the blend. However, the amount of crystallization increased significantly with the higher molecular weight sPLLA, therefore the star-shaped structure may play a role as nucleating agent. PLLA-polyethylene glycol–PLLA triblock copolymers (PEGLA) with different PLLA block length were synthesized and their applicability as blends with linear PLLA (3051D NatureWorks) was investigated with the intention of improving heat-seal and adhesion properties of extrusion-coated paperboard. PLLA-PEG-PLLA was obtained by ring opening polymerization (ROP) of L-lactide using PEG (molecular weight 6000 g mol-1) as an initiator, and stannous octoate as catalyst. The structures of the PEGLAs were characterized by proton nuclear magnetic resonance spectroscopy (1H-NMR). The melt flow and thermal properties of all PEGLAs and their blends were evaluated using dynamic rheology, and differential scanning calorimeter (DSC). All blends containing 30 wt% of PEGLAs showed slightly higher zero shear viscosity, higher shear thinning and increased melt elasticity (based on tan delta). Nevertheless, no significant changes in thermal properties were distinguished. High molecular weight PEGLAs were used in extrusion coating line with 3051D without problems.

Effect of ambient conditions on dimensional stability and stiffness of commercial paperboard and paperboard trays

The objective of this study was to develop laboratory test methods for characterizing the effects of changed moisture content on paperboard trays produced by press-forming process. Influence of moisture on the properties of unconverted paperboard such as bending stiffness, bursting strength, and curling was studied. Paperboard and tray samples were tested after storing in different relative humidity conditions (35, 50, 65, 80 and 95% RH). The effect of PE and PET extrusion coatings on these properties was also studied. It was found that increase in moisture content of paperboard decreases bending and bursting strength, dimensional stability and stiffness of paperboard trays. Such physical and mechanical properties as bending stiffness and curling of paperboard seem to define the stiffness of ready-made trays and their dimensional stability. Paperboards and trays with extruded PE and PET one sided coatings demonstrated higher strength properties but at the same time had lower dimensional stability comparing to uncoated paperboards. Samples with smaller polymer coat weight had better dimensional stability than respective samples with higher coat weight. It was also found that preconditioning of paperboard in lower humidity environment before press-forming could improve dimensional stability and stiffness of ready-made tray.

Storage stability of snacks with reduced saturated and trans fatty acids contents

Partially hydrogenated vegetable oil has been used in snack flavoring for its ability to entrap hydrophobic aroma compounds. However, increasing concerns about the health risks of saturated and trans fatty acids (TFA) consumption led to the development of alternative agents for this use. We studied the use of rapeseed oil (O) as a replacement for partially hydrogenated vegetable oil (F) in snack flavoring. Products with several different rapeseed oil contents were designed, packed, and then stored for twenty weeks at room temperature. Fatty acids compositions, TBA reactive substances (TBARS), shear strength and sensory acceptability were assessed throughout storage time. Total replacement reduced saturated fat by 72.5% in relation to market available snacks. TFA were initially absent in these products, but their production occurred spontaneously on the 8th week with gradual increase during storage up to levels still lower than those observed in commercially available snacks. Low TBARS levels and stability of shear strength during the twenty-week of storage were also observed. Snacks flavored with F or O were equally well accepted during the storage period. It is feasible to develop a storage stable snack with reduced saturated and trans fatty acid contents while maintaining the high sensory acceptability typical of this food product.

Effect of sugar and water contents on non-expanded cassava flour extrudates

The effects of sucrose and water contents on cassava flour processed by extrusion at varied concentrations of sucrose (0-20% w/w) and water (28-42% w/w) were studied by applying response surface methodology. The extrusion of the mixtures was performed in a twin screw extruder fitted to a torque rheometer. The specific mechanical energy (SME) dissipated inside a conical twin-screw extruder was measured. Water absorption index (WAI), water solubility index (WSI) and paste viscosity readings (cold viscosity (CV), peak viscosity (PV), breakdown (BD) and set back (SB)) during a gelatinization-retrogradation cycle measured in a Rapid Visco Analyzer were determined on non-directly extruded products. The results indicated that SME and WSI decreased as a function of water and sucrose contents. WAI and pasting properties were influenced by water content. A non antiplasticizing effect of the sucrose content was observed on pasting properties, suggesting that sucrose did not reduce the availability of water available for gelatinizing cassava flour during the extrusion process. The nature of the optimum point was characterized as a saddle point for WAI, WSI, PV and BD, whereas SME showed a maximum and CV and SB a minimum. The results indicated to be valuable for the production of non-expanded cassava flour extrudates with desirable functional properties for specific end users.

Effects of defatted amaranth (Amaranthus caudatus L.) snacks on lipid metabolism of patients with moderate hypercholesterolemia

We evaluated the effects of defatted amaranth (Amaranthus caudatus L.) snacks on plasma lipids in moderate hypercholesterolemic patients. Twenty-two subjects [30-65 years old), 11 males, with total cholesterol (TC) > 240 mg.dL-1, low-density cholesterol (LDL-c) 160-190 mg.dL-1 and plasma triglycerides (TG) < 400 mg.dL-1] were randomized in a double blind clinical trial to receive an amaranth snack (50 g/day) or equivalent corn snack (placebo) for 2 months. There were no differences between amaranth and placebo on TC and LDL-c, and TG respectively: -8.4 and -5.7% (p = 0.17); -12.3 and -9.7% (p = 0.41) and -0.6 and -7.3% (p = 0.47). However, amaranth snacks significantly reduced high-density cholesterol (HDL-c): -15.2 vs. -4% (p = 0.03). In conclusion, the intake of 50 g of extruded amaranth daily during 60 days did not significantly reduce LDL-c in moderate hypercholesterolemic subjects; furthermore there was a significant reduction in HDL-c. Studies with greater number of subjects and greater quantity of this food are necessary to test the effects of amaranth on lipid metabolism in humans.

Pre-treatment of thermoduric spores in CO2 modified atmosphere and their survivability during food extrusion

The aim of this experiment was to evaluate how susceptible spores become to mechanical damage during food extrusion after being submitted to CO2. B. stearothermophilus spores sowed to corn and soy mix were submitted to 99% CO2 for 10 days and extruded in a single-screw extruder. The treatments were: T1 - spore-containing samples, extruded at screw rotational speed of 65 rpm and barrel wall temperature of 80 °C; T2 - as T1, except for screw rotational speed of 150 rpm; and T3 - as T2, except that samples were submitted to the modified atmosphere. The results for cell viability, minimum and maximum residence times, and static pressure were T1 - 19.90 ± 3.24%, 123.3 ± 14.50 seconds; 203.3 ± 14.05 seconds; 2.217 ± 62 kPa; T2 - 21.42 ± 8.24%, 70.00 ± 5.77 seconds; 170.00 ± 4.67 seconds; 2.310 ± 107 kPa; and T3 - 11.06 ± 2.46%, 86.00 ± 7.23 seconds; 186.00 ± 7.50 seconds; 2.403 ± 93 kPa, respectively. It was concluded that the extrusion process did reduce the cell count. However, screw rotational speed variation or CO2 pre-treatment did not affect cell viability.

Modified broken rice starch as fat substitute in sausages

The demand for low-fat beef products has led the food industry to use fat substitutes such as modified starch. About 14% of broken rice is generated during processing. Nevertheless, this by-product contains high levels of starch; being therefore, great raw material for fat substitution. This study evaluated the applicability of chemically and physically modified broken rice starch as fat substitute in sausages. Extruded and phosphorylated broken rice was used in low-fat sausage formulation. All low-fat sausages presented about 55% reduction in the fat content and around 28% reduction in the total caloric value. Fat replacement with phosphorylated and extruded broken rice starch increased the texture acceptability of low-fat sausages, when compared to low-fat sausages with no modified broken rice. Results suggest that modified broken rice can be used as fat substitute in sausage formulations, yielding lower caloric value products with acceptable sensory characteristics.

Optimization of extrusion process for production of nutritious pellets

A blend of 50% Potato Starch (PS), 35% Quality Protein Maize (QPM), and 15% Soybean Meal (SM) were used in the preparation of expanded pellets utilizing a laboratory extruder with a 1.5 × 20.0 × 100.0 mm die-nozzle. The independent variables analyzed were Barrel Temperature (BT) (75-140 °C) and Feed Moisture (FM) (16-30%). The effect of extrusion variables was investigated in terms of Expansion Index (EI), apparent density (ApD), Penetration Force (PF) and Specific Mechanical Energy (SME), viscosity profiles, DSC, crystallinity by X-ray diffraction, and Scanning Electronic Microscopy (SEM). The PF decreased from 30 to 4 kgf with the increase of both independent variables (BT and FM). SME was affected only by FM, and decreased with the increase in this variable. The optimal region showed that the maximum EI was found for BT in the range of 123-140 °C and 27-31% for FM, respectively. The extruded pellets obtained from the optimal processing region were probably not completely degraded, as shown in the structural characterization. Acceptable expanded pellets could be produced using a blend of PS, QPM, and SM by extrusion cooking.

Technological properties of precooked flour containing coffee powder and rice by thermoplastic extrusion

Although Brazil is a country of tradition in both the production and consumption of coffee, the most of the coffee is consumed as a beverage, which reduces greatly the competitiveness on international market, for reducing the chances of supplying the product under other forms of consumption. Owing to that, the aim of this study was developing a precooked mixed flour containing coffee powder and rice for use in coffee flavored products. Mixtures of rice and coffee in the proportions of 900:100, 850:150 and 800:200 g, respectively, were processed in a single screw extruder (Brabender DS-20, Duisburg, German) and the effect of the extrusion process on the variables moisture content (16%, 18% and 20%) and temperature in the third extruding zone (140 °C, 160 °C and 180 °C) was studied. The results for expansion index ranged from 2.91 to 11.11 mm in diameter; the water absorption index from 4.59 to 6.33 g gel/g sample and the water solubility index varied from 4.05% to 8.57%. These results showed that, despite coffee powder influenced the variables studied, the expanded product after milling resulted in a extruded mixture with good absorption and water solubility indices, which favors the use of the precooked mixed flour for human consumption.

Optimization of extrusion variables for the production of snacks from by-products of rice and soybean

This study aimed to define the process conditions to obtain snacks from the by-products of rice and soybean with physical characteristics suitable for marketing. Therefore, the effects of moisture and extrusion temperature on the expansion and color of the products obtained experimentally obtained were evaluated, and the proximate composition of the by-products and that of the snack with greater desirability were determined. Response surface methodology and rotational central composite design were used, and desirability test based on the regression models adjusted was applied. The most desirable snack, with the highest expansion index (3.39), specific volume (13.5 mL.g-1), and the chromaticity coordinate a* (2.79), was obtained under 12 g.100 g-1 moisture and 85ºC of temperature in the third zone of the extruder. The snack produced under these conditions attained content of protein and lipid content 41 and 64% higher than that of the traditional corn snack. It can be concluded that producing extruded snack made form a mixture of broken grains, rice bran, and soybean okara (81:9:10) is technologically feasible, enabling the development of a new product with good nutritional value that can improve the diet of children, the main consumers of this type of food.