Letteratura scientifica selezionata sul tema "Shelf life of macadamia nuts"

Pine nut (Pinus pinea L.) is a nutritious, expensive tree nut. During storage, it is exposed to a wide range of environmental deteriorative conditions. This study describes the oxidative stability of pine nuts kept in pouches made of three different packaging materials and stored at three different temperatures. The packaging materials evaluated were low-density polyethylene (LDP), high-density polyethylene (HDP), and high-barrier metallized film (MF). Temperatures evaluated were 4, 20, and 60°C. In addition, a control unpacked sample was also evaluated in identical conditions. The oxidative parameters evaluated were acid value and peroxide value. Data analyses include a shelf-life study and a principal component analysis. The results obtained indicate what the best packaging material at 20°C was MF with a shelf-life of 703 d. At 4°C, the shelf-life of pine nuts stored in HDP was 1148 d. It is concluded that it is fundamental to use an adequate packaging to protect the seeds from environmental conditions that promote deterioration.

Abstract Rujak kawista sauce is one of the typical Indonesian foods made from palm sugar, tamarind, bird’s eye chili, nuts, and special fruits of kawista to enhance the flavour. There is no information about the shelf-life of rujak kawista sauce to date. Therefore, it is necessary to conduct a study on the storage time of the rujak kawista sauce to determine the product’s shelf life. This study used the ASLT method to determine the shelf life of rujak sauce. The sauce was stored at temperatures of 30°C, 40°C, and 50°C within 21 days storage time and was analysed every seven days. The analytical methods used to support the ASLT method are TBA, moisture content, FFA, total dissolved solids and pH. The result showed that TBA value was 0.046-0.19 mg malonaldehyde/kg, moisture content was 16.68-20%, FFA was 0.66-0.80%, total dissolved solid was 17.9-21.1°Brix, and pH was 3.1-3.5. Based on Arrhenius calculations, the shelf-life of rujak kawista sauce was two months.

Areca fruit (Areca catechu) has traditionally been used as a tooth strengthening and whitener through the habit of “chewing,” in Indonesian culture. In Madura, the use of young areca nuts is an herbal medicine for male virility. Wider utilization has not been performed, even though betel nuts contain bioactive compounds, potentially as antimicrobials. The aim of this research was to obtain evidence for the use of watery extract of betel nuts as a natural ingredient to extend fruits’ shelf life from fungal attacks. The fungus isolated from melon fruit was Meyerozyma sp., and the isolate from banana fruit was Aspergillus sp. Extraction of betel nuts using water as a solvent produces a dark brown concentrated solution. The in vitro antifungal test result showed that the inhibitory activity of areca flesh water extract against fungal isolates was still lower than that of 0.2% ketoconazole. The in vivo test results on “Arumanis” mangoes and “Ambon” bananas with Aspergillus sp. from bananas showed that hyphae had not appeared on days 4 and 5 of storage at room temperature 25 oC, respectively. Areca fruit extract can extend the shelf life of the fruit at room temperature.

Shelf life in ground and tree nuts are often assessed based on aesthetic appearance, nut integrity, color and most importantly, taste and edibleness. Nuts with considerable level of rancidity and free fatty acids due to degradation of oils indicate expiration or decay. We prepared a shellac-lemongrass oil blend coating using food-grade ingredients and assessed its potential to extend shelf life of Pili nut (Canarium ovatum) kernels. A glossy, hard but considerably brittle coating for the pili kernels were prepared with varying numbers of layers. On average, the mass of coating added per dip is 0.10 g, and the thickness of 5-layers of coating is 0.3 mm. The obtained reflectance spectra of the coated pili kernels implied the translucent nature of the coating, but becomes opaque as the number of layers are increased. Peroxide value (PV) and free fatty acid value (FFAV), were also measured at 10 days after application of coating. PV was lowest in the nuts with 5 coating layers, while this treatment did not reduce FFAV. These results indicate the effectiveness of our coatings in preventing peroxide production probably by blocking oxygen penetration and ultraviolet exposure, which are important triggers production of peroxide and other free radicals. Further tests and time-series experiments are planned to assess the dynamics of peroxide levels and the overall potential of our coating technology for Pili nut.

Nuts are very nutritive generally used in food and beverages preparation. In modern perspective, the shelf life extension and its quality is important parameter to be taken in consideration for its processing in food industry. Microbiological and chemical studies have been carried on different batches of received raw nuts stored in woven sack bag contained LDPE bag. For reducing microbial load in nuts four method of treatment was chosen. They are autoclave sterilization, Hot air oven pasteurization, Vacuum oven pasteurization, Microwave oven pasteurization. All four methods temperature kept constant and time is varying. In autoclave sterilization there will be nil microbial count and increasing in all physic-chemical parameters. In vacuum oven pasteurization there will be decreasing in microbial load as the time increasing. And all physic-chemical parameters are coming within specification. In hot air oven pasteurization there will be decreasing in microbial load as the time increasing but sensory and physic-chemical properties of almonds got affected. In micro wave oven sensory parameters of nuts got affected as the time increasing there will be development of roasting flavour and texture of nuts became crunchy.

Nuts are widely consumed worldwide, mainly due to their characteristic flavor and texture, ease of consumption, and their functional properties. In addition, consumers increasingly demand natural or slightly processed foods with high quality. Consequently, non-thermal treatments are a viable alternative to thermal treatments used to guarantee safety and long shelf life, which produce undesirable changes that affect the sensory quality of nuts. Non-thermal treatments can achieve results similar to those of the traditional (thermal) ones in terms of food safety, while ensuring minimal loss of bioactive compounds and sensory properties, thus obtaining a product as similar as possible to the fresh one. This article focuses on a review of the main non-thermal treatments currently available for nuts (cold plasma, high pressure, irradiation, pulsed electric field, pulsed light, ultrasound and ultraviolet light) in relation to their effects on the quality and safety of nuts. All the treatments studied have shown promise with regard to the inhibition of the main microorganisms affecting nuts (e.g., Aspergillus, Salmonella, and E. coli). Furthermore, by optimizing the treatment, it is possible to maintain the organoleptic and functional properties of these products.

For optimal usage of new oil resources with high nutritional values, in this study, one chilgoza pine variety was provided, and assays of physicochemical characteristics of its nut such as moisture, ash, thousand nut weight, oil, protein, hull contents, density, pH and also physicochemical characteristics of its extracted oil by n-hexan solvent such as iodine values, saponification and unsaponification, peroxide, specific weight, acid values, moisture of oil, color (Lovibond) and fatty acid profile and extracted oil characteristics by cold press such as total polyphenols, tocophrols, carotenoids, chlorophylls, sterols, color (Hunterlab), DPPḢ and antioxidant were investigated. Then its effect as a natural antioxidant on rapeseed oil shelf life (without any antioxidant) was studied. The results indicated that chilgoza pine oil is belonged to linoleic-oleic group. Oil of chilgoza pine has α and γ tocopherols and there is no β and δ tocopherols on it. The oil of chilgoza pine, were mixed at two levels of 2% and 5% with rapeseed oil and these mixed were determined by peroxide, TBA and Rancimat indices during 0, 5, 10, 20 and 35 days and compared with control. Statistical results showed no antioxidant effect in shelf life of rapeseed oil at more days. This means that the chilgoza pine oil antioxidant compounds were not enough to prevent oxidative rancidity of rapeseed oil or maybe the antioxidant compounds of nuts were not migrated to oil.

Shelf life studies of raw Macadamia integrifolia nuts were carried out at different storage temperatures, relative humidities and time. An accelerated shelf life test was conducted, and the influence of water activity on kernel texture was studied. The antioxidants naturally present were identified by the use of thin layer chromatography. Accelerated shelf life tests showed that hydrolytic rancidity followed apparent zero order kinetics within the water activity range of 0.3 to 0.5. Oxidative rancidity measured by peroxide value appeared to follow different orders of reaction at different temperatures. At two months of storage rancidity was detected at which the headspace concentration of hexanal was 0.39 ppm and a peroxide value of 0.37 meq/kg. Headspace gas chromatography was done to find a quick and effective method for measuring oxidative rancidity. The presence of natural antioxidants was verified to explain the shelf life of macadamia nuts. In textural study, correlations were found between subjective and objective measurements. The product became unacceptable organoleptically above water activity 0.415 when stored at 20 degrees C. This level was established as the critical water activity. There is a need to establish a water activity at which the consumer is likely to reject the product.

Shelf life studies of raw Macadamia integrifolia nuts were carried out at different storage temperatures, relative humidities and time. An accelerated shelf life test was conducted, and the influence of water activity on kernel texture was studied. The antioxidants naturally present were identified by the use of thin layer chromatography. Accelerated shelf life tests showed that hydrolytic rancidity followed apparent zero order kinetics within the water activity range of 0.3 to 0.5. Oxidative rancidity measured by peroxide value appeared to follow different orders of reaction at different temperatures. At two months of storage rancidity was detected at which the headspace concentration of hexanal was 0.39 ppm and a peroxide value of 0.37 meq/kg. Headspace gas chromatography was done to find a quick and effective method for measuring oxidative rancidity. The presence of natural antioxidants was verified to explain the shelf life of macadamia nuts. In textural study, correlations were found between subjective and objective measurements. The product became unacceptable organoleptically above water activity 0.415 when stored at 20 degrees C. This level was established as the critical water activity. There is a need to establish a water activity at which the consumer is likely to reject the product.
Master of Science (Hons) (Food Science and Nutrition)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Brazil nut (Bertholletia excelsa) and Macadamia (Macadamia integrifolia) are rich feeds with excellent nutrients with higher quality. The main form of consumption of these nuts and almonds are in natura, but there are products which can be elaborated using these raw materials with high nutritional value and pleasant flavor. Water-soluble extracts are an alternative to consume them, which consist of fluid food of plant origin, that can be produced by nuts, oleaginous and even some grasses and they have great commercial appeal since they are free of animal’s fats, “lac free” (free of lactose) and have high rate of minerals. Thus, this research aimed to determine the best formulation, to accompany physical and microbiological stability, proximal composition, to estimate the shelf life and to determine the rheological behavior of a water-soluble extract made of Brazil nut and Macadamia. For the construction of mathematical models, with the purpose of knowing the effect of the variation of water, Brazil nut and Macadamia concentrations, basic components in the elaboration of the product on the proximal composition and physical aspects such as pH, titratable acidity and colorimetry, a simplex centroid design for mixtures was used and provided quadratic and cubic models showing excellent adjustment of experimental data. The Global Acceptance and Purchase Intention tests were performed for each experiment proposed by simplex centroid design and the Tukey test was used in order to determine the best proportion among the components of the ternary mixture. The formulation of water-soluble extract composed of 70% (w/w) water, 15% (w / w) Brazilian nut and 15% (w/w) Macadamia was considered to be the most preferred by tasters submitted to the sensory evaluations. In order to improve the product’s flavor, 10% (w/v) of sugar, expressed as sucrose, was added and the concentration of preservatives citric acid, potassium sorbate and sodium benzoate was reduced. The product was processed technologically under hygienic conditions and filled in 220 ml transparent glass bottles, hermetically sealed with metal crown cork, pasteurized at 80 °C/25 min, stored under refrigeration at 4 ° C and had its stability evaluated during 28 days. Growth of Thermotolerant Coliforms, Positive Coagulase Staphylococci, Salmonella sp, Molds and Yeasts during the evaluation period was not detected. There was a significant variation (p < 0.05) in pH in the first two weeks of storage, and remained without significant variation (p > 0.05) for the other weeks analyzed. The acidity remained constant throughout the lifetime. The product showed a yellowish-white color throughout the study, determined by the coordinates of the colorimetry. Sensory analysis scores for odor, color, taste and global impression averaged around 6, thus, concluding that the product has a 28 days of shelf life. The rheological profile of the beverage was evaluated at three different temperatures, at 25 °C (room temperature), at 45 °C (temperature of the disintegration stage of Brazil nut and Macadamia with water in blender), and at 80 °C, (pasteurization temperature). The Ostwald-de-Waele model was considered the best to describe the beverage flow and since the calculated flow rate of the model, was less than 1 at the temperatures studied, it had concluded that the beverage behaved as a fluid Non-Newtonian pseudoplastic. The apparent viscosity curves of the mixed drink were plotted and showed that the apparent viscosity decreased significantly (p < 0.05) with the increasing of temperature.
A Castanha-do-Brasil (Bertholletia excelsa) e a Macadâmia (Macadamia integrifolia) são alimentos ricos em nutrientes de excelente qualidade. A principal forma de consumo de nozes e amêndoas é in natura, porém existem produtos que podem ser elaborados a partir destas matérias-primas com alto valor nutricional e também de sabor agradável. Uma alternativa ao consumo desses alimentos são os extratos hidrossolúveis, que consistem em alimentos fluidos de origem vegetal que podem ser produzidos a partir de castanhas, oleaginosas e até mesmo algumas gramíneas e possuem grande apelo comercial, uma vez que são isentos de gorduras animais, não possuem lactose e apresentam alto teor de minerais. Sendo assim, esta pesquisa objetivou determinar a melhor formulação, acompanhar a estabilidade física e microbiológica, composição proximal, estimar a vida útil e determinar o comportamento reológico de um extrato hidrossolúvel a base de Castanha-do-Brasil e Macadâmia. Para a construção de modelos matemáticos, com a finalidade de se conhecer o efeito da variação das concentrações de água, Castanha-do-Brasil e Macadâmia, dos componentes básicos na elaboração do produto sobre a composição proximal e aspectos físicos como pH, acidez titulável e colorimetria, utilizou-se o planejamento experimental para misturas tipo simplex centroide que forneceu modelos quadráticos e cúbicos com excelente ajuste frente aos dados experimentais. Os Testes de Aceitação Global e Intenção de Compra foram realizados para cada experimento proposto pelo planejamento simplex centroide e o teste de Tukey foi utilizado a fim de determinar a melhor proporção entre os componentes da mistura ternária. A formulação de extrato hidrossolúvel composta por 70% (p/p) de água, 15% (p/p) de Castanha-do-Brasil e 15% (p/p) de Macadâmia, foi considerada como a mais preferida pelos provadores submetidos as avaliações sensoriais. Com a finalidade de melhorar o sabor do produto, adicionou-se 10% (p/v) de açúcar, expressos em sacarose, e reduziu-se a concentração dos conservantes ácido cítrico, sorbato de potássio e benzoato de sódio. O produto foi processado tecnologicamente sob condições higiênicas, sendo envasado em garrafas de vidro transparente de 220 mL, fechado hermeticamente com tampas metálicas do tipo coroa, pasteurizado a 80 °C/25 min, armazenado sob refrigeração a 4 °C e teve sua estabilidade avaliada por 28 dias. Não foi detectado o crescimento de Coliformes Termotolerantes, Estafilococos Coagulase Positiva, Salmonella sp, Bolores e Leveduras durante o período de avaliação. Houve variação significativa (p < 0,05) do pH nas duas primeiras semanas de estocagem, estabilizando-se para as demais semanas analisadas. A acidez se manteve constante durante todo o período de vida útil. O produto apresentou coloração branco-amarelada durante todo o estudo, determinada pelas coordenadas da colorimetria. As notas das análises sensoriais para Odor, Cor, Sabor e Impressão Global tiveram média em torno de 6, concluindo assim que o produto tem vida útil de, pelo menos, 28 dias. Foi avaliado o perfil reológico da bebida em três temperaturas distintas, a 25 ºC (temperatura ambiente), a 45 ºC, (temperatura da etapa de desintegração da Castanha-do-Brasil e Macadâmia com a água em liquidificador), e a 80 ºC, (temperatura de pasteurização). O modelo de Ostwald-de-Waele foi considerado o melhor para descrever o escoamento da bebida e uma vez que o índice de escoamento calculado do modelo foi menor que 1, nas temperaturas estudadas, conclui-se que a bebida comportou-se como um fluido não newtoniano pseudoplástico. As curvas de viscosidade aparente da bebida mista foram plotadas e mostram que a viscosidade aparente diminuiu significativamente (p < 0,05) com o aumento da temperatura.

Brazil nuts (Bertholletia excelsa, H.B.K.) are seeds of high nutritional value collected from South American rainforests and its productive chain is one of the most important non-timber economic activities in Brazilian amazon. The main objectives of this research were: 1) characterize the occurrence of chemical changes in Brazil nut kernels (BNK), cold-pressed Brazil nut oil (BNO) and Brazil nut flour obtained by water extraction (BNF); and 2) investigate strategies of control and monitoring these changes during storage. For this, consolidated techniques, such as spectrophotometry and chromatography, and a relatively new analytical technique, the electron spin resonance (ESR) spectroscopy, were employed. As major results, it was found that different combinations of storage temperatures and atmosphere packages have differently affected the tendency of radical formation and off-flavor volatile aroma compounds generation in BNK, and that the combination of refrigeration with vacuum packing was able to keep BNK at their best. It was demonstrated that a spin-trapping ESR spectroscopy method would be suitable to monitor oxidative changes in BNO with known history stored either in clear or in brown glass bottles under retail conditions. For BNF, it was demonstrated that minor variations on water activity (aw) might significantly affect the rates of both lipid oxidation and nonenzymatic browning reactions during storage. There was indication that for BNF with initial aw of 0.196, but not for BNF with initial aw of 0.101, under the studied conditions, secondary products from lipid oxidation might be substrates for nonenzymatic browning products formation. As a conclusion, these results may help to better understand chemical deteriorative processes in BNK and its co-products, according to the storage conditions, and that the use of less sample-demanding, fast and solvent-free analytical method to monitor these changes in BNO is feasible.
A castanha do Brasil (Bertholletia excelsa, H.B.K.) é uma semente de boa qualidade nutricional coletada em florestas tropicais da América do Sul, cuja cadeia produtiva é uma das mais importantes atividades econômicas não madeireiras da Amazônia brasileira. Os principais objetivos desta pesquisa foram: 1) caracterizar a ocorrência de alterações químicas em castanhas do Brasil (CB), óleo de castanha do Brasil obtido por prensagem a frio (OCB) e farinha de castanha do Brasil obtida por extração aquosa (FCB); e 2) investigar estratégias para controlar e monitorar essas alterações ao longo do armazenamento. Para isso, técnicas consolidadas como a espectrofotometria e a cromatografia, e uma técnica relativamente recente, a espectroscopia de ressonância de spin eletrônico (RSE), foram empregadas. Dentre os principais resultados obtidos, foi possível constatar o efeito de diferentes combinações de temperaturas e atmosferas de embalagem sobre a tendência de formação de radicais e sobre a geração de compostos voláteis de aroma relacionados a odor indesejável em CB, e que a temperatura de refrigeração combinada com a embalagem a vácuo foi a mais eficiente na preservação da qualidade da CB. Demonstrou-se que o uso de um método de aprisionamento de spins de RSE pode ser eficiente para monitorar alterações químicas em OCB com histórico conhecido embalado em frascos de vidro transparente ou marrons sob condições de armazenamento comercial. Para FCB, foi demonstrado que pequenas variações na atividade de água (aw) podem afetar significativamente as taxas de oxidação lipídica e de reações de escurecimento não enzimático durante armazenamento. Obteve-se indicação de que para FCB com aw inicial de 0,196, mas não para FCB com aw inicial de 0,101, produtos secundários da oxidação lipídica podem ser substratos para a formação de produtos do escurecimento não enzimático. Como conclusão geral, os resultados obtidos podem ajudar a explicar melhor os processos de deterioração química em CB e seus coprodutos, conforme as condições de armazenamento, e que o uso de um método que requer menor quantidade de amostras, é rápido e não usa solventes é viável para o monitoramento da qualidade de OCB.

The research was conducted to investigate the production of value-added tea as part of the resuscitation of Tshivhase-Mukumbani Tea Estate. Data were mainly obtained from records kept at the Tshivhase-Mukumbani Tea Estate, through a review of literature and interviews of the selected respondents. Evaluation of economic viability of the value-adding initiative was based on Net Present Value (NPC) and the Benefit-Cost Ratio (BCR) calculated from time-series data obtained for the period 2005–2012. The quantity of value-added tea produced varied across years, geographical locations, and seasons, with production higher for wetter seasons. The NPV was consistently negative, while the BCR was below unity throughout the study period, implying that the value-adding initiative was economically not feasible. Initiatives for achieving economic sustainability of the value addition were (1) Improve the marketing of the made tea brand Midi Tea as organic and longer shelf life. (2) Good labor contracting management practices to deal with labor disputes and unrest. (3) Good supply chain and procurement management practices to reduce the cost of production (4) Monitoring the impact of climate variability and mitigate by providing irrigation (5) Intercropping tea with a suitable winter yielding crops such as avocadoes or Macadamia.

Lipids play a crucial role in defining functionality, processing and sensory properties of confectionery products. In applications, such as chocolates and compound coatings, the fat is the continuous phase where other ingredients (sugar, milk powders, cocoa powders, nuts, emulsifiers, etc) are dispersed and determines the physical and textural properties of the final product. For confectionery fillings, the type of fat used affects the sensory properties of the filling, its compatibility with the other components and the shelf life of the product. Formulation of most lipid-based confectionery products requires the use of structuring fats to provide the required functionality. Thus, the crystallization and subsequent network formation of high-melting triglycerides (TAGs) is needed to create a structural framework that can physically trap low-melting TAGs (liquid oil) into a three-dimensional gel-like structure. Alternative approaches for oil structuring based on gelator molecules working as building blocks have been researched over the last years. However, the conventional route based on crystalline TAGs is still a valid approach in product development and routinary production of oils and fats processors.  The aim of this work is to show some practical examples of raw material evaluation within confectionery fats manufacturing and its impact on oils structuring, processing, product recipes and functionality. Among others, we will review the behavior of TAGs from cocoa butter and cocoa butter alternatives in compound coatings and the crystallization of liquid oils on confectionery fillings. Some analytical methods and techniques, such as differential scanning calorimetry (DSC) and cooling curves (Jensen, Buhler Crystallization Index), will also be discussed.