Utjecaj proteina graha lima na funkcionalna svojstva škroba

The functional properties of starches determine their potential applications in food systems. These properties depend largely on granular and molecular structure and can be physically, chemically or enzymatically modified. One way of modifying starch functional properties is by interaction with other food components, such as proteins. Starch-protein interactions are frequent in plant foods, particularly cereals and legumes, which are formed mainly of starches and proteins. An evaluation has been done of changes in the functional properties of three native starches (corn, Zea mays L.; cassava, Manihot esculenta; and lima bean, Phaseolus lunatus L.) when blended with lima bean protein concentrate. The gelatinization temperature of each blend increased compared to its corresponding native starch. The cassava starch/lima bean protein blend had the highest overall swelling power and water absorption capacity values at all temperatures. Maximum viscosity for each blend was higher than for the corresponding native starches. The blends of lima bean protein with cassava and corn starches did not exhibit syneresis. The lima bean starch/lima bean protein blend had the highest gel firmness values, followed by the blends with corn and cassava starches. The protein-starch mixtures are an alternative in the improvement of the starch functional properties which are useful in the development of nutritional products.O funkcionalnim svojstvima škroba ovisi njegova primjena u proizvodnji hrane. Ta svojstva uglavnom ovise o strukturi zrna i molekula. Mogu se modificirati fizikalnim, kemijskim ili enzimskim postupcima, a jedan od njih je i interakcija s ostalim sastojcima hrane (npr. proteinima). Interakcije škroba i proteina su česte u hrani biljnog podrijetla, osobito u žitaricama i leguminozama koje se uglavnom sastoje od te dvije komponente. U radu je ispitana promjena funkcionalnih svojstava škroba izoliranog iz kukuruza (Zea mays L.), manioke (Manihot esculenta) i lima graha (Phaseolus lunatus L.), nakon miješanja s koncentratom proteina iz graha lima. Temperatura se želiranja svake mješavine škroba i proteina povećala u usporedbi s izvornim škrobom. Mješavina škroba manioke i proteina graha lima imala je najbolji kapacitet bubrenja i upijanja vode na svim temperaturama. Maksimalna je viskoznost mješavina bila veća od viskoznosti samog škroba svake vrste, pri čemu mješavine proteina graha lima sa škrobom manioke i kukuruza nisu pokazale jače zgrušavanje. Najveću je čvrstoću gela imala mješavina škroba i proteina graha lima, zatim mješavina škroba kukuruza i proteina, te naposljetku škroba manioke i proteina graha lima. Mješavine su škroba i proteina alternativni način poboljšavanja funkcionalnih svojstava škroba u proizvodnji hrane

Nontuberculous Mycobacterial Keratitis

AbstractNon-tuberculous mycobacteria are environmental, opportunistic pathogens that are increasingly being recognized as important causes of many human diseases. Among them, rapidly growing mycobacteria are the most notorious organisms causing infectious keratitis. Nontuberculous mycobacterial (NTM) keratitis commonly occurs after trauma or refractive surgery, and can masquerade as fungal, herpetic or amoebic keratitis. Therefore, the diagnosis is often delayed. Prolonged medical treatment and judicious surgical debridement are required in order to eradicate the pathogens. Combination therapy with aminoglycosides, macrolides and fluoroquinolones improves the prognosis and decreases the occurrence of drug resistance. However, regardless of the development of new diagnostic techniques and antimicrobials, NTM keratitis remains a clinical challenge for most ophthalmologists. In this article, we provide a concise introduction to the epidemiological features and clinical characteristics of NTM keratitis, and the modern diagnostic tools used for it. We also summarize the current concepts of prevention and treatment for this potentially devastating condition

Hydrolyzates from Pyropia columbina seaweed have antiplatelet aggregation, antioxidant and ACE I inhibitory peptides which maintain bioactivity after simulated gastrointestinal digestion

The aim of this work was to evaluate the bio-accessibility of bioactive peptides with ACE I inhibition, antioxidant and antiplatelet aggregation activity obtained by enzymatic hydrolysis of Pyropia columbina proteins. Two hydrolyzates were produced (A and AF). Bio-accesibility was determined using a gastrointestinal digestion (pepsin and pancreatin) and membrane dialysis system. Hydrolyzates had peptides with medium molecular weight (2300 Da), and Asp, Glu and Ala were the most abundant amino acids. Additionally, AF presented small peptides with 287 Da. Peptides from A showed the highest angiotensin-converting enzyme activity (ACE I) inhibition by uncompetitive mechanism (IC50%, 1.2 ± 0.1 g L−1), and β-carotene bleaching inhibition. Peptides from AF presented the lower IC50% value for ABTS+• and DPPH radical inhibition, the highest copper-chelating activity (CCA), and antiplatelet aggregation activity. In vitro gastrointestinal digestion increased ABTS+• and DPPH scavenging and CCA of both hydrolyzates. Antiplatelet aggregation activity of A peptides was increased after simulated digestion process (≈157%). Peptides from both hydrolyzates were potentially bio-accessible, maintaining overall the bioactivity after gastrointestinal digesFil: Cian, Raúl Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología de los Alimentos; ArgentinaFil: Garzón, Antonela Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología de los Alimentos; ArgentinaFil: Betancur, Ancona, David. Universidad Autónoma de Yucatán; MéxicoFil: Chel Guerrero, Luis. Universidad Autónoma de Yucatán; MéxicoFil: Drago, Silvina Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología de los Alimentos; Argentin

Study of the Interaction of Phaseolus lunatus Hydrolysed Proteins and Delonix regia Carboxymethylated Gum Using Capillary Electrophoresis

Proteins and gums are commonly employed in the manufacture of processed foods. The knowledge of the degree of interaction between these two types of biopolymers is important for the development of new products and processes. In this work, the interaction of protein hydrolysate (PH) of Phaseolus lunatus with carboxymethylated flamboyant gum (CFG) was evaluated. Capillary electrophoresis technique was performed using a P/ACE MDQ equipment with diode array detector at 220 nm, using a 50 μm I.D. bare fused-silica capillary, with a 20 cm effective length, operating at 5 kV for injection and separation in reverse polarity at 15 kV and 25 °C. PH presented 7 main protein components of 8.3, 11.2, 12.9, 17.0, 19.1, 28.7 and 56.4 kDa. A standard curve with different concentrations of hydrolysed protein (3.8 to 8.6 g/L) was prepared by linking the relative peak height for each component present in the protein hydrolysate to its concentration. To determine the existence of PH-CFG interaction, protein-gum mixtures using different concentrations of PH and keeping constant the concentration of CFG at 2 or 2.8 g/ L were evaluated. Interaction PH-CFG was observed at 1.8-2.9 protein / gum ratios. Protein components of PH presented a tendency to join to CFG in a greater extent at lower molecular weight. Protein components higher than 20 kDa remain free in PH-CFG systems.Fil: Corzo Rios, Luis Jorge. Universidad Autónoma de Yucatán; México. Instituto Politécnico Nacional; MéxicoFil: Drago, Silvina Rosa. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología de los Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Gallegos Tintoré, Santiago. Universidad Autónoma de Yucatán; MéxicoFil: Betancur Ancona, David. Universidad Autónoma de Yucatán; MéxicoFil: Chel Guerrero, Luis. Instituto Politécnico Nacional; Méxic

Sinteza pirodekstrina i maltodekstrina iz škroba makala (Xanthosoma yucatanensis), otpornog na djelovanje enzima

Research background. Enzymatically resistant maltodextrins (ERM) are a resistant starch type 4, synthesized from native starch. They are obtained by the sequential application of two processes: pyrodextrinization, which produces pyrodextrins, and enzymatic hydrolysis, which produces ERM. In these processes atypical bonds are formed that confer pyrodextrins and ERM similar properties to dietary fiber, such as resistance to digestion. The aim of this work is to determine and evaluate some physicochemical properties of pyrodextrins and ERM obtained from native starch isolated from makal (Xanthosoma yucatanense) tubers. Experimental approach. Pyrodextrinization and complementary hydrolysis were conducted using factorial designs. For pyrodextrinization, factors and their levels were (m(starch):V(HCl))=80:1 and 160:1 (c(HCl)=2.2 M), temperature 90 and 110 °C and reaction time 1 and 3 h, and for CH, α-amylase per pyrodextrin volume fractions 0.5 and 1 µL/mL and reaction time 10 and 30 min. The physicochemical profile included determination of resistant starch content, estimation of color change (ΔE), microscopy and determination of dextrose equivalents (DE). Results and conclusions. According to the factorial design, the best treatment conditions for pyrodextrinization were: (m(starch):V(HCl))=160:1, 90 °C and 3 h, since they resulted in the highest resistant starch content (84.73 %) and the lowest ΔE (3.742). Due to the low DE (13.89 %), increased amount of resistant starch (90.73 %) and low ΔE (4.24) in the resulting ERM, complementary hydrolysis with α-amylase per pyrodextrin volume fraction 0.5 µL/mL and hydrolysis time 10 min was selected as the best treatment. Novelty and scientific contribution. The results show that the pyrodextrins and ERM obtained from makal can be used as ingredients for the development of functional foods, due to their high content of indigestible material and low degree of browning.Pozadina istraživanja. Maltodekstrini otporni na djelovanje enzima su rezistentni škrobovi tipa 4, sintetizirani iz prirodnog škroba. Dobivaju se uzastupnom primjenom dvaju procesa: pirodekstrinizacijom, tijekom koje nastaju pirodekstrini, te enzimskom hidrolizom, pri kojoj nastaju maltodekstrini otporni na djelovanje enzima. Tijekom tih procesa se formiraju atipične veze koje pirodekstrinima i rezistentnim maltodekstrinima daju svojstva nalik onima prehrambenih vlakana, kao što je otpornost na probavne enzime. Svrha je ovog rada bila odrediti i procijeniti neka fizikalno-kemijska svojstva pirodekstrina i rezistentnih maltodekstrina dobivenih iz izoliranog prirodnog škroba gomolja makala (Xanthosoma yucatanense). Eksperimentalni pristup. Primjenom faktorijalnog dizajna provedena je pirodekstrinizacija uz prateću hidrolizu. Faktori i njihove vrijednosti korišteni pri provedbi pirodekstrinizacije bili su: (m(škrob):V(HCl))=80:1 i 160:1 (c(HCl)=2.2 M), temperatura 90 i 110 °C, te vrijeme reakcije 1 i 3 h, a za enzimsku hidrolizu bili su: volumni udjel α-amilaze od 0.5 i 1 µL po mL pirodekstrina, te vrijeme reakcije 10 i 30 min. Fizikalno-kemijska analiza obuhvaćala je određivanje udjela rezistentnog škroba, procjenu promjene boje (ΔE), mikroskopsku analizu i određivanje dekstroznih ekvivalenata (DE). Rezultati i zaključci. Prema faktorijalnom dizajnu najbolji su uvjeti pirodekstrinizacije bili: (m(škrob):V(HCl))=160:1, 90 °C i 3 h, jer su rezultirali najvećim udjelom rezistentnog škroba (84,73 %) i najnižim ΔE (3,742). Zbog niske vrijednosti DE (13,89 %), većeg udjela rezistentnog škroba (90,73 %) i niskog ΔE (4,24) u dobivenom rezistentnom maltodekstrinu, dodatna hidroliza s volumnim udjelom α-amilaze od 0.5 µL po mL pirodekstrina i vremenom hidrolize od 10 min odabrana je kao najbolji postupak. Novina i znanstveni doprinos. Rezultati pokazuju da se pirodekstrini i rezistentni maltodekstrin, dobiveni iz makala, mogu koristiti kao sastojci za razvoj funkcionalnih namirnica, zbog velikog udjela neprobavljivog materijala i niskog stupnja tamnjenja

RNAi Screen of Endoplasmic Reticulum–Associated Host Factors Reveals a Role for IRE1α in Supporting Brucella Replication

Brucella species are facultative intracellular bacterial pathogens that cause brucellosis, a global zoonosis of profound importance. Although recent studies have demonstrated that Brucella spp. replicate within an intracellular compartment that contains endoplasmic reticulum (ER) resident proteins, the molecular mechanisms by which the pathogen secures this replicative niche remain obscure. Here, we address this issue by exploiting Drosophila S2 cells and RNA interference (RNAi) technology to develop a genetically tractable system that recapitulates critical aspects of mammalian cell infection. After validating this system by demonstrating a shared requirement for phosphoinositide 3-kinase (PI3K) activities in supporting Brucella infection in both host cell systems, we performed an RNAi screen of 240 genes, including 110 ER-associated genes, for molecules that mediate bacterial interactions with the ER. We uncovered 52 evolutionarily conserved host factors that, when depleted, inhibited or increased Brucella infection. Strikingly, 29 of these factors had not been previously suggested to support bacterial infection of host cells. The most intriguing of these was inositol-requiring enzyme 1 (IRE1), a transmembrane kinase that regulates the eukaryotic unfolded protein response (UPR). We employed IRE1α(−/−) murine embryonic fibroblasts (MEFs) to demonstrate a role for this protein in supporting Brucella infection of mammalian cells, and thereby, validated the utility of the Drosophila S2 cell system for uncovering novel Brucella host factors. Finally, we propose a model in which IRE1α, and other ER-associated genes uncovered in our screen, mediate Brucella replication by promoting autophagosome biogenesis