Rui Carlos Zambiazi

Colour, lipid and protein stability of Rhea americana meat during air- and vacuum-packaged storage: influence of muscle on oxidative processes.

Physicochemical characteristics and oxidative stability during storage were determined in Gastrocnemius pars interna (GN) and Iliofiburalis (IF) muscles of Rhea americana. Glycolytic potential (GP) and pH decline of muscles were measured within the first 24 h post mortem. Colour, lipid and protein stability were determined during storage of meat, i.e. 5 days under air-packaging at 4°C, or 28 days under vacuum-packaging at 4°C. In parallel, anti-oxidant status of muscles was estimated by measuring α-tocopherol content and anti-oxidant enzyme activities (superoxide dismutase and catalase), while pro-oxidant status was evaluated by determining haeminic iron and long chain fatty acids (especially polyunsaturated fatty acids). The ultimate pH was similar in both muscles, but the GP value was significantly higher in IF than in GN muscle. Haeminic iron and alpha-tocopherol content differed between muscles, with 30% more haeminic iron (p<0.05) and 134% more alpha-tocopherol (p<0.001) in IF than GN muscle. The IF muscle presented higher lipid content and lower PUFA/SFA ratio (polyunsaturated fatty acids/saturated fatty acids) than GN muscle. With storage under air-packaging, lipid and protein oxidation of rhea muscles increased up to 275% and 30%, respectively. This increase was more rapidly and marked in IF muscle. The IF also showed high level of metmyoglobin accumulation after 3 days of storage (47%) and was rejected by 1 consumer out of 2 in sensorial analysis. Under vacuum-packaging, both muscles showed a high stability of colour and no oxidation of lipids and proteins.

γ-Oryzanol and tocopherol contents in residues of rice bran oil refining

Rice bran oil (RBO) contains significant amounts of the natural antioxidants γ-oryzanol and tocopherols, which are lost to a large degree during oil refining. This results in a number of industrial residues with high contents of these phytochemicals. With the aim of supporting the development of profitable industrial procedures for γ-oryzanol and tocopherol recovery, the contents of these phytochemicals in all the residues produced during RBO refining were evaluated. The samples included residues from the degumming, soap precipitation, bleaching earth filtering, dewaxing and deodorisation distillation steps. The highest phytochemical concentrations were found in the precipitated soap for γ-oryzanol (14.2 mg g(-1), representing 95.3% of total γ-oryzanol in crude RBO), and in the deodorisation distillate for tocopherols (576 mg 100 g(-1), representing 6.7% of total tocopherols in crude RBO). Therefore, among the residues of RBO processing, the deodorisation distillate was the best source of tocopherols. As the soap is further processed for the recovery of fatty acids, samples taken from every step of this secondary process, including hydrosoluble fraction, hydrolysed soap, distillation residue and purified fatty acid fraction, were also analyzed. The distillation residue left after fatty acid recovery from soap was found to be the best source of γ-oryzanol (43.1 mg g(-1), representing 11.5% of total γ-oryzanol in crude RBO).

Scientific note: bioactive compounds in small fruits cultivated in the southern region of Brazil.

Summary The nutritional value is one of the main factors that fuels the growing interest in fruit consumption, but the properties and beneficial activities to human health of many fruits of smaller national expression have still not been properly defined. These foods possess different bioactive compounds and thus the objective of this work was to evaluate the total bioactive compound contents, more specifically the phenols, anthocyanins and carotenoids, in Surinam cherries (Eugenia uniflora L.), pindo palm (Butia capitata), blackberry (Rubus spp.) cv. Tupy and cv. Xavante, blueberry (Vaccium ashei) cv. Blue Powder and cv. Delite and loquats (Eribrotia japonica). The fruits were collected during the 2006 harvest from the Embrapa Temperate Climate orchard (Pelotas/RS). The samples were collected and immediately frozen at –80 °C in an ultra-freezer until the moment of analysis. The total phenol contents of cherry purple, red and orange Surinam, pindo palm, blackberry cv. Tupy and cv. Xavante, blueberry cv. Powder Blue and cv. Delite and loquat were 420.8; 239.2; 201.8; 328.6; 645.5; 731.4; 816.9; 750.5 and 55.8 mg of gallic acid.100 g –1 , respectively. With respect to the anthocyanin contents, the values were 138.7; 96.4; 4.1; 0.0; 47.7; 45.2; 128.0; 72.0 and 0.0 mg of cyanidin 3-glycoside.100 g–1 of fruit, respectively. The carotenoid contents were 90.6; 153.0; 60.7; 28.0; 9.1; 6.0; 1.4; 10.8 and 24.0 µg of β carotene.g –1 of fruit, respectively. It was observed that amongst the fruits studied the richest source of phenolic compounds was the blackberry, and the richest source of anthocyanins was the purple Surinam cherry. The red Surinam cherry was the fruit presenting the highest carotenoid content.

Estabilidade de compostos bioativos em polpa congelada de amora-preta (Rubus fruticosus) cv. Tupy

O Brasil e considerado um dos principais paises consumidores de frutas, ocupando a terceira posicao mundial. A diversidade de frutas destinadas ao mercado e cada vez maior, mas suas propriedades e atividades nao estao totalmente determinadas. No entanto, a partir do inicio da decada de 90, a grande oferta de frutas vem justificando estudos direcionados ao desenvolvimento de novos produtos, que, na maioria das vezes, concentra na fruta in natura e na polpa suas maiores formas de consumo. Este trabalho teve por objetivo elaborar polpa de amora-preta da cultivar Tupy, e armazena-la sob diferentes condicoes de temperaturas (-10, -18 e -80 oC) durante 6 meses, e avaliar a estabilidade de seus principais fitoquimicos apos o processamento e durante o periodo de armazenamento. Os resultados demonstraram que a temperatura de -10°C foi suficiente para nao causar alteracoes significativas com relacao a fenois totais, antocianinas totais, capacidade antioxidante e acidez titulavel (2 meses). A temperatura de -18°C foi suficiente para nao causar alteracoes significativas nas polpas com relacao a: fenois totais e capacidade antioxidante (4 meses), antocianinas totais (2 meses) e β-caroteno (6 meses). Na temperatura de -80°C, poucas foram as alteracoes causadas na polpa armazenada por 6 meses, sendo observado apenas pequenas alteracoes em solidos soluveis, acido hidroxibenzoico. Nos carotenoides totais e individuais nenhuma das tres temperaturas fpi suficiente para evitar as perdas. Nos tocoferois, apenas na polpa armazenada a -80°C por 2 meses nao houve alteracao. E o acido ascorbico foi totalmente degradado nos 6 meses de armazenamento nas duas temperaturas (-10 e -18°C). Os compostos que mais contribuiram para o poder antioxidante da amorapreta cv. Tupy foram os compostos fenolicos.

Microencapsulation of palm oil by complex coacervation for application in food systems

This study aimed at microencapsulating palm oil, containing high carotenoid content, with chitosan/xanthan and chitosan/pectin, using the complex coacervation method, followed by atomization and lyophilization. The DSC technique was used to confirm the encapsulation. The atomized microparticles had spherical shape and irregular size, and the lyophilized microparticles had irregular shape and size. Lyophilization resulted in lower carotenoids losses, and higher yield and encapsulation efficiency. In addition, the release profile in both water and gastrointestinal fluid was satisfactory. Prior to their application in food, a greater percentage of carotenoids was released in the fluid that simulates gastrointestinal conditions; however, the compounds were degraded after their release. In this case, the chitosan/pectin microparticles showed the best release profile. After processing, the release was lower and the released compounds were not degraded. Thus, the chitosan/xanthan microparticles showed the best potential for practical application, particularly, in yogurt preparation.

Elaboration of microparticles of carotenoids from natural and synthetic sources for applications in food

Carotenoids are susceptible to isomerization and oxidation upon exposure to oxygen, light and heat, which can result in loss of color, antioxidant activity, and vitamin activity. Microencapsulation helps retain carotenoid stability and promotes their release under specific conditions. Thus, the aim of the study was to encapsulate palm oil and β-carotene with chitosan/sodium tripolyphosphate or chitosan/carboxymethylcellulose and to assess the performance of these microparticles in food systems by analyzing their release profile under simulated gastric and intestinal conditions. Encapsulation efficiency was greater than 95%, and the yield of microparticles coated with chitosan/sodium tripolyphosphate was approximately 55%, while that of microparticles coated with chitosan/carboxymethylcellulose was 87%. Particles encapsulated with chitosan/carboxymethylcellulose exhibited ideal release behavior in water and gastric fluid, but showed low release in the intestinal fluid. However, when applied to food systems these particles showed enhanced carotenoid release but showed low release of carotenoids upon storage.

Nutritional value and digestion rate of rhea meat proteins in association with storage and cooking processes.

The nutritional value of proteins was investigated after the storage and cooking of rhea M. Gastrocnemius pars interna. Oxidation of basic and aromatic amino acids, surface hydrophobicity and aggregation state of proteins, were determined in raw and cooked meat. In addition, myofibrillar proteins were exposed in vitro to proteases of the digestive tract. Cooking markedly affected the protein surface hydrophobicity. The BBP bound content was three times greater in cooked than in fresh rhea meat. A small increment in tryptophan content after cooking was observed. Storage influenced Schiff bases formation indicating the presence of protein-aldehyde adducts after cooking. High content of Schiff bases was found after cooking of samples stored for 5 days, demonstrating a probable implication of free amino groups, most likely from lysine. Cooking decreased the myofibrillar protein susceptibility to pepsin activity. After cooking, the proteolysis rate by pancreatic enzymes increased. Our findings support the importance of protein aggregation in the nutritional value of meat proteins.

Effect of frozen storage duration and cooking on physical and oxidative changes in M. Gastrocnemius pars interna and M. Iliofiburalis of Rhea americana.

This study was conducted to evaluate the effect of frozen storage time (30, 60, 90 or 180 days) and cooking (100 °C, 30 min) on the physical characteristics and oxidative stability of M. Gastrocnemius pars interna (GN) and M. Iliofiburalis (IF) of rhea americana. Physical parameters measured included thawing and cooking loss, colour parameters (L*a*b*), while oxidation was assessed by determining the TBA-RS, carbonyl and aromatic amino acid content. Prolonged frozen storage of rhea meat decreased lightness (L*), yellowness (b*), and increased the discoloration parameter hue angle and redness a*. During storage, muscle IF was more prone to lipid and myoglobin oxidation than muscle GN. Cooking loss declined with the increase of storage time and was higher in GN than in IF muscle. With cooking, TBA-RS, carbonyl content, and aromatic amino acids (phenylalanine, tyrosine, and tryptophan) were highly affected, but the extent of oxidation ranged according to muscle and duration of frozen storage.

Quantification of Several Bioactive Compounds and Antioxidant Activities of Six Cultivars of Brazilian Blueberry

The Bioactive composition of blueberries has attracted interest as a potential source of beneficial bioactive compounds, especially polyphenols, because the consumption of plant phenolics and others bioactive compounds has been recognized as lowering the risk of aging-associated diseases. Berries such as the Brazilian blueberry (Vaccinium ashei Reade) are increasingly cultivated throughout the world. In Brazil, its cultivation is rather recent and not well- known. However, Brazil has an ideal climate and has a great potential for increasing production. The study aimed to identify and quantify the major bioactive compounds in the skin, pulp and entire fruit of six Brazilian blueberry cultivars belonging to the group Rabbiteye, and to evaluate its antioxidant activity. Determinations of L-ascorbic acid, tocopherols, phenolics, individual carotenoids and antioxidant activity were done. These determinations were made on Powderblue, Briteblue, Bluebelle, Climax, Delite and Woodard cultivars, provided by Embrapa Clima Temperado, Pelotas-RS. The blueberry fruits are rich sources of phenolic compounds but other bioactive compounds such as tocopherols, carotenoids and vitamin C also were found. All phytochemicals analyzed, with the exception of some phenolic acids, were found at high levels in the peels (or skin) of blueberry cultivars tested, due to its function as plant protector, resulting in a higher antioxidant activity of fruit peel.

Caracterização física, química, microbiológica e sensorial de geléias light de abacaxi

O trabalho objetivou elaborar geleias com reduzido teor calorico, utilizando como agentes de corpo diferentes combinacoes dos hidrocoloides xantana, carragena e locusta. Como comparativo utilizou-se uma formulacao padrao de geleia de abacaxi (controle), elaborada com sacarose e xarope de glicose na proporcao de 4:1 (p/p), e com teor final de solidos soluveis de 65oBrix. As quatro formulacoes light foram preparadas pela substituicao de 50% da quantidade de acucar da formulacao controle, sendo que para equiparar a docura, adicionou-se o edulcorante sucralose. Foram avaliadas as caracteristicas quimicas, fisicas, microbiologicas e sensoriais, alem do valor calorico total das geleias. Os resultados mostraram que as geleias apresentaram caracteristicas quimicas e fisicas semelhantes as descritas na literatura e enquadraram-se na categoria de produtos light, segundo a legislacao vigente. Quanto as caracteristicas microbiologicas, todas as formulacoes enquadraram-se nos padroes microbiologicos estabelecidos pela legislacao brasileira. Em termos sensoriais a formulacao com a combinacao das gomas carragena:xantana:locusta (1:1:1, p/p/p) foi a que apresentou melhores caracteristicas de geleia.