Prediction of Bioactive Peptides from Chicken Feather and Pig Hair Keratins using In Silico Analysis Based on Fragmentomic Approach.

BACKGROUND: Keratin is among the most abundant structural proteins of animal origin, however it remains broadly underutilized. OBJECTIVE: Bioinformatic investigation was performed to evaluate selected keratins originating from mass-produced waste products, i.e., chicken feathers and pig hair, as potential sources of bioactive peptides. METHODS: Pepsin, trypsin, chymotrypsin, papain, and subtilisin were used for in silico keratinolysis with the use of "Enzyme(s) action" and fragmentomic analysis of theoretical products was performed using "Profiles of potential biological activity" in BIOPEP-UWM database of bioactive peptides. Bioactivity probability calculation and toxicity prediction of the peptides obtained were estimated using PeptideRanker and ToxinPred tools, respectively. RESULTS: Our results showed that the keratins are a potential source of a variety of biopeptides, including dipeptidyl peptidase IV, angiotensin converting enzyme, prolyl endopeptidase inhibitory and antioxidative. Papain and subtilisin were found to be the most appropriate enzymes for keratin hydrolysis. This study presents possible structures of keratin-derived bioactive peptides that have not been previously described. CONCLUSION: Our data suggest additional in vitro and in vivo studies to verify theoretical predictions and further investigate the possibility of using keratin-rich waste as a source of peptide nutraceuticals.

Decellularized liver-regenerative 3D printing biomaterials for cell-based liver therapies via a designed procedure combining supercritical fluids with papain-containing reagents.

BACKGROUND: The biologic scaffolds derived from decellularized tissues and organs have been successfully developed in a variety of preclinical and/or clinical studies. OBJECTIVE: The new decellularized liver-regenerative 3D printing biomaterials were designed and prepared for cell-based liver therapies. METHODS: An extraction process was employed to remove the tissue and cellular molecules from porcine liver via pretreatment of supercritical fluid of carbon dioxide (ScCO2). Varying porosities of the decellularized liver tissues were created using papain-containing reagent treatments after ScCO2. RESULTS: The resulting liver-regenerative 3D printing biomaterials of decellularized liver collagen scaffolds were characterized by Fourier transform infrared spectroscopy, thermo-gravimetric analysis, differential scanning calorimetry and scanning electron microscopy. CONCLUSIONS: The decellularized liver collagen scaffolds with good thermal stability (>150 °C) were obtained and employed as liver-regenerative 3D printing biomaterials for cell-based liver therapies.

A Molecular Probe with Both Chromogenic and Fluorescent Units for Detecting Serine Proteases.

A molecular probe with l-phenylalanine p-nitroanilide and l-lysin 4-methylcoumaryl-7-amide, in which these amino acid derivatives are connected through a succinic-acid spacer, was prepared. Trypsin and papain were detected by blue-fluorescence emission of generated 7-amino-4-methylcoumarin (AMC). α-Chymotrypsin and nattokinase were detected from both the blue-fluorescence emission of AMC and the UV absorbance of p-nitroaniline. In addition, different time courses of p-nitroaniline and AMC were observed between the reaction of P1 with α-chymotrypsin and that with nattokinase. In the case of nattokinase, both the fluorescence emission and UV absorbance slowly increased. In contrast, the increasing UV absorbance was saturated at the early stage of the reaction of the present probe with chymotrypsin, whereas the fluorescence emission continuously increased in the following stages.

Identification of Antigens in Immune Complexes.

Comprehensive identification and profiling of antigens in immune complexes (IC-antigens) is useful to provide insights into pathophysiology and could form the basis for novel diagnostic and treatment strategies for many immune-related diseases. Immune complexome analysis is the method for comprehensively identifying and profiling IC-antigens in biological fluids (such as serum and cerebrospinal fluid). Here, we describe an IC-antigen detection method; specifically, ICs in biological fluids are captured by using protein G- or protein A-coated beads, are subjected to papain-digestion, elution, and tryptic digestion, and are analyzed by nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS).

Improving the physico-chemical and sensory characteristics of camel meat burger patties using ginger extract and papain.

The objective of the current study was to include tenderizing agents in the formulation of camel meat burger patties to improve the physico-chemical and sensory characteristics of the product. Camel meat burger patties were processed with addition of ginger extract (7%), papain (0.01%) and mixture of ginger extract (5%) and papain (0.005%) in addition to control. Addition of ginger, papain and their mixture resulted in significant (P<0.05) increase of the collagen solubility and sensory scores (juiciness, tenderness and overall acceptability) with significant (P<0.05) reduction of the shear force values. Ginger extract resulted in extensive fragmentation of myofibrils; however, papain extract caused noticeable destructive effect on connective tissue. Moreover, ginger and papain resulted in improvement of the lipid stability of treated burger patties during storage. Therefore, addition of ginger extract and papain powder during formulation of camel burger patties can improve their physico-chemical and sensory properties.

A resonance light scattering sensor based on bioinspired molecularly imprinted polymers for selective detection of papain at trace levels.

A novel resonance light scattering sensor based on the molecularly imprinted polymers (MIPs) technique was developed for specific recognition of the trace quantities of papain (Pap). In this sensor, as the specific recognition element, an excellent biocompatibility of protein-imprinted polymer without fluorescent materials was easily prepared, which based on the effective synthesis of mussel-inspired bionic polydopamine (PDA) on the surface of SiO2 nanoparticles (SiO2@PDA NPs). This recognition element could capture the target protein selectively, which led to the enhancement of resonance light scattering intensity with the increasing of the target protein concentration. The sensor was applied to determine Pap in the linear concentration range of 2.0-20.0 nM with a correlation coefficient r = 0.9966, and a low detection limit of 0.63 nM. The relative standard deviation for 14 nM of Pap was 1.02% (n = 7). In addition, the specificity study confirmed the resultant Pap-imprinted SiO2@PDA NPs had a high-selectivity to Pap, and the practical analytical performance was further examined by evaluating the detection of Pap in the dietary supplement with satisfactory results, with good recoveries of 97.5-105.3%.

Upgrading food wastes by means of bromelain and papain to enhance growth and immunity of grass carp (Ctenopharyngodon idella).

The fast growing of global aquaculture industry accompanied with increasing pressure on the supply and price of traditional feed materials (e.g., fish meal and soy bean meal). This circumstance has urged the need to search alternative sources of feed stuff. Food waste was used as feed stuff in rearing fish which possess substantial protein and lipid. Grass carp are major species reared in Hong Kong with lower nutritional requirements; it is also an ideal species for investigating the feasibility of using food waste as fish feeds for local aquaculture industry. The growth and immunity, reflected by total protein, total immunologlobulin (IgI), and nitroblue tetrazolium (NBT) activity of grass carp blood, were depressed when feeding with food waste feeds without enzymes. However, the supplementation of bromelain and papain in fish feed enhanced the efficient use of food waste by grass carp, which in turn improved the fish immunity. The present results indicated that the addition of those enzymes could enhance the feed utilization by fish and hematological parameters of grass carp, and the improvement on growth and immunity superior to the control (commercial feed) was observed with the addition of bromelain and papain supplement. Addition of 1 and 2 % mixture of bromelain and papain could significantly enhance the lipid utilization in grass carp.

Análise sazonal da produção e da atividade enzimática de látex fresco coletado de frutos de plantas femininas e hermafroditas de mamão (Carica papaya L. ) / Seasonal analysis of yield and enzyme activity of fresh latex collected from fruits of female and hermaphrodite plants of papaya (Carica papaya L. )

RESUMO O látex obtido do fruto de Carica papaya L. (mamão) é de grande importância industrial e farmacêutica. Sua obtenção, através do cultivo dessa espécie, depende de vários fatores ainda pouco estudados. Nesse sentido, o presente trabalho tem por objetivo avaliar e comparar plantas femininas e hermafroditas de C. papaya em relação à produção de látex e sua atividade enzimática em coletas semanais e consecutivas durante o 12º mês de cultivo (verão) e no decorrer do segundo ano de desenvolvimento das plantas, e em mais três coletas abrangendo as demais estações do ano (outono, inverno e primavera). Os resultados mostraram que, em quatro coletas semanais e sucessivas durante o verão, a massa de látex da primeira coleta foi superior às demais para plantas femininas. Plantas hermafroditas tiveram comportamento oscilante para esta variável. Plantas femininas tiveram médias de produção superiores comparadas com as hermafroditas. As médias das atividades enzimáticas desse período se mostraram superiores para plantas hermafroditas. Nas coletas estacionais foi observado que plantas hermafroditas têm um comportamento mais oscilante em relação à produção de látex e atividade enzimática. Plantas femininas produzem, em média, maior massa de látex e são mais constantes na produção. Nas estações avaliadas, observaram-se semelhanças nas médias das atividades enzimáticas entre plantas femininas e hermafroditas.

ABSTRACT The latex obtained from the fruit of Carica papaya L. (papaya) is of great industrial and pharmaceutical importance. Its obtainment, through the cultivation of this specie, depends on several factors still poorly studied. In this sense, this study aims to evaluate and compare hermaphrodite and female plants of C. papaya for the production of latex and its enzymatic activity in weekly and consecutive collections of fruits during the 12th month of cultivation (summer) and during the second year of the plant´s development, in three collections covering the other seasons (autumn, winter and spring). The results showed that, in four successive weekly tapping during the summer, the latex mass of the first collection was superior to the others, for female plants. Hermaphrodite plants had oscillating behavior for this variable. Female plants had higher production averages, compared with the hermaphrodites ones. The averages of the enzymatic activities of this period were higher for hermaphrodite plants. The seasonal tapping showed that hermaphrodite plants had oscillating behavior in the production of latex and enzyme activity. Female plants produced, on average, greater mass and were constant in latex production. In the evaluated seasons, similarities in the averages of the enzymatic activities between female and hermaphrodite plants were observed.

Multivalent photoaffinity probe for labeling small molecule binding proteins.

Characterization of small molecule (SM)-protein interaction is of high importance in biomedical research such as target identification and proteomic profiling. Photo-cross-linking is a powerful and straightforward strategy to covalently capture SM's binding proteins. The DNA-based photoaffinity labeling method is able to capture SM's protein targets with high specificity but suffers low cross-linking efficiency, which limits its utility for low abundance and low affinity proteins. After screening a variety of cross-linkers, by utilizing the multivalency effect, the cross-linking efficiency was improved by nearly 7-fold without compromising probe specificity. The generality and performance of multivalent photoaffinity probes have been validated with a variety of SM-protein pairs in the complexity of cell lysates.

Influence of papain in biofilm formed by methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus haemolyticus isolates

Methicillin-resistant Staphylococcus epidermidis (MRSE) and methicillin-resistant Staphylococcus haemolyticus (MRSHa) are important coagulase-negative staphylococci. They are often isolated from bacteremia in humans mainly due to their ability to form biofilm on the surfaces of medical devices. Papain is a complex mixture of proteolytic enzymes and peroxidases extracted from the latex of Carica papaya and it is recognized by accelerating the healing process of wounds. This study aimed to evaluate the ability of the MRSE and MRSHa isolates to produce biofilms. Besides this, the ability of papain to inhibit the formation of biofilms or to disrupt the ones already formed by those bacteria was analyzed. Thirty MRSHa and 30 MRSE were isolated from bacteremia and used in this study. It was observed that papain has ability to reduce biofilms formed by MRSE (p < 0.06) and by MRSHa (p = 0.0005). In addition, papain was able to disrupt mature biofilms made by MRSE (p = 0.014). No antibacterial activity of papain was observed for any isolates of MRSE and MRSHa tested. Papain has been demonstrated as a potential product for reducing biofilm.

Staphylococcus epidermidis resistente à meticilina (MRSE) e Staphylococcus haemolyticus resistente à meticilina (MRSHa) são importantes estafilococos coagulase negativa. São frequentemente isolados em bacteremia humana, principalmente devido à capacidade de formar biofilmes nas superfícies de dispositivos médicos introduzidos no organismo. A papaína é mistura complexa de enzimas proteolíticas e peroxidases extraídas do látex de Carica papaya, reconhecida por acelerar os processos de cura de feridas. Este estudo teve como objetivo avaliar a capacidade dos MRSE e MRSHa em produzir biofilmes e analisar a capacidade da papaína em inibir a formação de biofilme ou desintegrar biofilmes já formados por essas bactérias. Observou-se que a papaína tem capacidade de reduzir a formação de biofilme por MRSE (p < 0,06) e MRSHa (p = 0,0005). Além disso, a papaína foi capaz de desintegrar biofilme maduro formado por MRSE (p = 0,014). Nenhuma atividade antibacteriana da papaína foi observada para qualquer das duas espécies de bactérias testadas. A papaína mostrou-se produto potencial para reduzir biofilme.

Tenderization effect of soy sauce on beef M. biceps femoris.

This study was conducted to evaluate the tenderization effect of soy sauce on beef M. biceps femoris (BF). Five marinades were prepared with 4% (w/v) sodium chloride and 25% (w/v) soy sauce solutions (4% salt concentration) and mixed with the ratios of 100:0 (S0, pH 6.52), 75:25 (S25, 5.40) 50:50 (S50, 5.24), 25:75 (S75, 5.05), and 0:100 (S100, 4.85), respectively. The BF samples which were obtained from Hanwoo cows at 48 h postmortem (n=24) were marinated with five marinades for 72 h at 4°C (1:4 w/w), and the effects of soy sauce on tenderness were evaluated. Soy sauce marination resulted in a decrease in the pH value of the BF sample. However, there were no significant differences in the water holding capacity (P<0.05). The S100 treatment showed the significant (P<0.05) increase in collagen solubility and myofibrillar fragmentation index, contributing to decreased shear force compared to S0 (control). Reduction in intensity of few myofibrillar protein bands were observed for S100 treatment compared to control using SDS-PAGE. Scanning electron microscopy revealed breakdown of connective tissue surrounding muscle fibers of the S100 treatment. The tenderization effect of soy sauce may attribute various mechanisms such as increased collagen solubility or proteolysis which depend on soy sauce level in marinade.

Simple and sensitive determination of papain by resonance light-scattering with CdSe quantum dots.

In this contribution, a simple and sensitive method for papain detection was established based on the increment of the resonance light-scattering (RLS) intensity of mercaptoacetic acid-capped CdSe quantum dots (MAA-QDs) in aqueous solution. Meanwhile, the RLS characteristics and the optimal conditions were investigated in detail. Under the optimized conditions, the linear range of MAA-QDs RLS intensity versus the concentration of papain was 1.0×10(-8) M to 6.0×10(-7) M, with a correlation coefficient (R(2)) of 0.9977 and a limit of detection (3σ black) of 5.1×10(-9) M. The relative standard deviation (R.S.D.) for 1.6×10(-7) M papain was 1.0% (n=5). There was almost no interference to coexisting foreign substances including common ions, proteins and 20 amino acids. The proposed method possessed the advantages of simplicity, rapidity and sensitivity. Three synthetic samples were analyzed by the methodology and the results were satisfying. The interaction between MAA-QDs and papain was also investigated systematically by using visual method, transmission electron microscopy and time-resolved fluorescence spectra, and the results indicated that the main force between MAA-QDs and papain was electrostatic interaction.

Study on the ternary system of MoO4 (2-) -enzyme-PdCl2 by resonance Rayleigh scattering, second-order scattering and frequency-doubling scattering spectra and its analytical application.

In pH 4.0 Britton-Robinson buffer medium, PdCl2 was able to react with enzymes (EZ) such as lysozyme (LYSO) and papain (PAP) to form a coordination complex (EZ-PdCl2 ), which further reacted with MoO4 (2-) to form a ternary complex (MoO4 (2-) -EZ-PdCl2 ). As a result, the absorption and fluorescence spectra changed; new spectra of resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency-doubling scattering (FDS) appeared and their intensities were enhanced greatly. The maximum RRS, SOS and FDS wavelengths of two ternary complexes were located at 310, 560 and 350 nm, respectively. The increments of scattering intensity were directly proportional to the concentrations of EZ within certain ranges. The detection limits (3σ) of LYSO and PAP were 4.5 and 14.0 ng/mL (RRS method), 9.6 and 57.8 ng/mL (SOS method), and 5.2 and 106.0 ng/mL (FDS method). Taking the MoO4 (2-) -LYSO-PdCl2 system, which was more sensitive, as an example, the effects of coexisting substances were evaluated. The methods showed excellent selectivity. Accordingly, new rapid, convenient, sensitive and selective scattering methods for the determination of LYSO and PAP were proposed and applied to determine LYSO in egg white with satisfactory results. The reaction mechanism and basis of the enhancement of scattering were discussed.

Ensaio clínico randonizado e duplo cego de curatios bioativos: cola de fibrina versus gel de papaína® no processo de cicatrização de úlceras crônicas de etiologia venosa / Randomized clinical essay and double-blind bioactive curatives: fibrin glue against papaya gel in the healing process of the chronic ulcers in a venous etiology

A UV traduz um dos estágios mais avançados da doença venosa crônica (DVC), e esta apresenta elevada morbidade pela sua cronificação e recidivas frequentes. Constitui importante problema de saúde pública por alterar a qualidade de vida do indivíduo e elevar o ônus público, já que os tratamentos são longos e dispendiosos. Apesar dos fatores de risco e a etiopatogenia desta doença serem conhecidos, grande parte da população usuária do sistema público de saúde não possui diagnóstico e tratamento precoces da DVC, resultando assim em evolução clínica tormentosa da doença. A dificuldade de avaliação com profissionais especializados predispõe a evolução da UV. Quando manejadas de formas inadequadas, as UVs tendem a tornar crônico o processo de cicatrização e ficam sujeitas a complicações como colonização crítica e infecção de partes moles. Esta revisão procura reunir informações atualizadas sobre a epidemiologia da DVC (enfocando principalmente dados do Brasil). Além disso, serão discutidos os fatores de risco, a etiopatogenia da UV e suas manifestações clínicas. Finalmente será feita uma atualização sobre os métodos auxiliares do processo de cicatrização da UV, expondo os avanços ao conhecimento relacionados a esta área, incluindo o preparo do leito da úlcera. O objetivo é propor mudanças que favoreçam a quebra do ciclo pernicioso da UV.

The VU is one of the most advanced stage` s chronic venous disease (CVD), and it has a high morbidity, because your recidivates are chronics and happens frequently. It is an important public health problem, because it modifies the quality of an individual and put up the public costs, since the medical treatment are longs and expensive. In spite of the risk factors and the studies of this disease are knew, a very part of the population, that use the public health utilities, don`t have diagnosis and CVD`S precocious medical treatment, for this reason the disease evolution is very hard. There is the evolution of the VU, because it is very difficult to evaluate it with an expert professional. The VUs can become chronics in a healing process, when they are badly controlled; they can dominate it and contaminate the soft parts. The objective of this revision is to join current in formations about CVD`s epidemiology (mainly Brazilian documents). Besides, the risk factors, the VU`s path physiology and their clinic manifestations will be discussed Finally, will be done an update about the auxiliary methods of the VU`s healing process, showing the know advances in this area, and how to prepare an ulcer bed. The object is to suggest changes that finish the VU`s pernicious cycle.

Comparative study of the stability of free and modified papain incorporated in topical formulations

Papain is an enzyme used in topical formulations as a proteolytic debriding agent for the treatment of open, extensive wounds and burnings. It is also employed as an enhancer for cutaneous permeation of active compounds, chemical peeling and as a progressive depilatory agent. The stability of formulations containing enzymes is not easy. In this research, papain was modified with polyethylene glycol in order to increase the stability of the formulations. The comparative Normal Stability Testing of the topical formulations containing unmodified and modified papain showed that the modified variety presented with a differentiated profile under the adopted temperature conditions (5.0 ± 1.0 °C; 22.0 ± 2.0 °C; 40.0 ± 2.0 °C). The most suitable condition for non-modified papain were 5.0 ± 1.0 °C and, for modified papain, they were 22.0 ± 2.0 °C. These results confirmed the higher stability of modified papain compared to free papain, as well as its potential to be applied in topical formulations.

A papaína é uma enzima utilizada em formulações tópicas como agente proteolítico debridante no tratamento de lesões abertas de grande extensão e queimaduras. É, também, empregada na pele íntegra como agente promotor da permeação cutânea de princípios ativos, peeling químico e como agente depilatório progressivo. A estabilidade de formulações contendo enzimas não é facilmente alcançada. No presente trabalho realizou-se a modificação da enzima com polietilenoglicol, visando maior estabilidade das formulações. A realização do Teste Estabilidade Normal comparativo entre as formulações contendo as formas da enzima não modificada e modificada demonstrou que a última apresentou um perfil de estabilidade diferenciado, nas diferentes condições (5,0 ± 1,0 °C; 22,0 ± 2,0 °C; 40,0 ± 2,0 °C). A condição de 5,0 ± 1,0 °C foi a mais adequada para a formulação contendo papaína não modificada enquanto a 22,0 ± 2,0 °C foi indicada para aquela contendo a forma modificada. Estes resultados confirmaram o aumento da estabilidade da papaína modificada comparada com a livre e seu potencial de aplicação em formulações de uso tópico.

A papaína reduz a formação de cápsula fibrosa ao redor de implantes de silicone texturizados em ratos / The papain pocket delivery impairs the capsule fibrous healing around texturedsilicone implants in rats

Objetivo: Estudar o reparo tecidual ao redor dos implantes mamários texturizados sob a açãolocal de papaína (PA). Método: Foram avaliados 36 ratos Wistar, distribuídos aleatoriamenteem dois grupos (n = 18): papaína (PA) e controle (CT). Cada grupo foi distribuído igualmenteem 3 subgrupos (n = 6) e observados nos períodos de 7, 35 e 90 dias pós-operatório. Cadaanimal recebeu um implante texturizado na região dorso-axilar à esquerda (sham - SH), sempapaína, onde se instilou previamente 0,5 mL de solução salina 0,9%; e outro implante tambémtexturizado à direita, onde se instilou 0,5 mL de solução hidrossolúvel contendo papaína. Osanimais do grupo controle (CT) receberam apenas inclusão de um implante texturizado naregião dorso-axilar esquerda com instilação prévia de 0,5 mL de solução salina 0,9%. A análisehistológica, nos 3 subgrupos, foi realizada utilizando-se a coloração de picrosirius red e umsistema analisador de imagens com o programa Image Pro Plus® para verificação da espessurae da densidade de fibras colágenas da cápsula. Resultados: No grupo papaína (PA),observou-se, aos 35 e 90 dias, diminuição significativa da espessura da cápsula fibrosa aoredor do implante, da densidade de fibras colágenas e da quantidade de miofibroblastos emcomparação ao grupo controle (CT). Conclusão: A papaína diminuiu a formação da cápsulafibrosa ao redor dos implantes de silicone texturizado em ratos.

Objective: To study the tissue repair around the textured mammary implants under the action ofpapain (PA). Methods: Thirty-six Wistar rats were evaluated and randomly distributed into twogroups (n = 18): papain (PA) and control (CT). Each group was equally distributed into 3 subgroups(n = 6) and observed on 7th, 35th and 90th pos-operative days. Each animal received a textured implantin the left dorso-axillary region (sham - SH), on were instilled 0.5 mL saline solution 0.9%, andanother textured implant on the right dorso-axillary region (papain - PA), on were instilled 0.5 mLof water-soluble solution of papain. The control group (CT) received only textured implant in theleft dorso-axillary region with prior instillation of 0.5 mL of saline solution 0.9%. The histologicalanalysis of the 3 subgroups was carried out using picrosirius-red stain and an image analyzingsystem using the Image Pro Plus™ program to evaluate the thickness and maturation anddeposition of collagen fibers. Results: At 35th and 90th days, the papain group (PA) presentedreduction on the fibrous capsule thickness around the implant, in the number of collagen fibersand myofibroblasts, comparing to the control group (CT). Conclusion: The papain drug decreasedthe fibrous capsule formation around the textured silicon implants in rats.

A pulse--radiolysis approach to fast reductive cleavage of a disulfide bond to uncage enzyme activity.

The essential thiol of the enzyme papain has been caged by linking to an aromatic thiol. The resulting caged protein is inactive but enzymatic activity is fully restored upon chemical cleavage of the protective disulfide bond. We have exploited the chemistry of this disulfide bond to uncage papain by pulse radiolysis. We have shown that up to 10% of the enzyme activity can be restored by reductive pulse radiolysis. This approach has been tested on a small-molecule model system, and experiments on this model compound show that pulse radiolysis of the mixed cysteine-aromatic disulfide results in selective reduction of the disulfide bond to generate a thiol in 10-20% yield, consistent with the radiolytically restored activity of the caged papain quantified by the biochemical assay.

[Resonance scattering spectral assay of papain enzymatic activity with sodium dodecyl benzene sulfonate].

In pH 6.5 phosphate buffer solutions, dodecyl benzene sulfonate (SDBS) was combined with casein to form association particles, which exhibited five Rayleigh scattering peaks at 470, 360, 400, 420 and 520 nm, respectively. Under suitable conditions, papain has catalytic effect on the hydrolysis of casein, and SDBS can stop the catalytic reaction and be combined with the excess casein to form association particles. The scattering peak at 470 nm decreased with the activity of papain. The delta I470 value was linear with the papain activity in the range of 0.048-4.8 USP x mL(-1). Its regress equation is delta I(SDBS) = 1.972c + 2.31, with a related coefficient of 0.9999 and detection limit of 0.020 USP x mL(-1). This new assay has been applied to the assay of the papain activity in food additive with satisfactory results.

The Surface Plasmon Resonance Imaging sensor for papain based on immobilized cystatin.

The Surface Plasmon Resonance Imaging (SPRI) sensor for papain determination based on the interaction between the immobilized cystatin and aqueous papain solution has been developed. The development of the sensor is a stage in the development of the sensor for the determination of cystein proteinases of the papain group. Cystatin was immobilized onto a gold chip by means of a thiol underlayer (cysteamine) and EDS/NHS reaction. Conditions of cystatin- papain interaction were optimized (pH, time of interaction and cystatin concentration). The developed sensor works within the range of 1 - 10 ng ml(-1). However, the precision of measurements (RSD equal to 45%) should be improved. The response of the sensor to papain is specific. This was checked using BSA as a reference.

Microencapsulamento de hidrolisados de caseína em lipoesferas para mascarar o sabor amargo: avaliação físico-química e sensorial / Microencapsulation of casein hydrolysates in lipospheres for debittering flavor: physical-chemistry and sensorial evaluation

A hidrólise enzimática de proteínas pode levar ao desenvolvimento de sabor amargo, associado à liberação de grupos hidrofóbicos. Neste trabalho, desenvolveu-se uma nova metodologia, baseada no encapsulamento em lipoesferas, para mascarar o sabor amargo de hidrolisados de caseína obtidos pela ação da papaína. Além disso, utilizou-se a espectrofotometria derivada segunda (EDS), como método de determinação da taxa de encapsulamento de hidrolisados enzimáticos de proteínas, e as amostras analisadas apresentaram valores em torno de 66 por cento. Este microencapsulamento mostrou ser uma tecnologia eficiente para reduzir a hidrofobicidade e o sabor amargo de hidrolisados de caseína...