Vitamin C occurs in relatively high concentrations in fresh and processed fruits and vegetables but is found to a lesser extent in animal tissues and animal-derived products. Nearly 90 % of vitamin C in the human diet is obtained from fruits and vegetables but this can be indirect by way of commercially prepared fruit juices. These juices are often enriched with vitamin C which has been synthetically prepared. There is a wide range of such juices on the New Zealand market, and they are a significant source of dietary vitamin C for many in the population. The focus of this research is on the Keri range of juice products.The present study monitors the fate of vitamin C during storage of Keri juices up to the best-before date, and under a range of other storage and consumption situations. Two methods were adopted for determining ascorbic acid (AA, the chemical identity of vitamin C). These were the titrimetric method, which is based upon the reduction of the dye 2,6-dichlorophenolindophenol by AA in acidic solution, and liquid chromatography, which is used to separate AA from its immediate oxidation product dehydroascorbic acid. In the latter method these two analytes can be measured independently. The liquid chromatography was less successful than the simpler titrimetric method, so most of the work was done by titration. However, the concentration of dehydroascorbic acid, which has vitamin C activity in vivo, remained uncertain. Moreover, the titrimetric method could not be applied to juices with high purple anthocyanin concentrations, like blackcurrant, because the colour change at the titration end point could not be detected. pH adjustment to change colour was ineffective, and decolourisation with charcoal led to the rapid and complete destruction of AA. The concentration of AA in Keri juices at the time of manufacture were always much higher than claimed on the labels. Storage for up to nine months at room temperature resulted in a loss in AA of between 37 and 68 %, depending on the juice and exposure to fluorescent light. However, the time of storage was a much more dominant factor than light exposure. The kinetics of loss, straight lines, were most easily explained by an aerobic model of AA degradation from oxygen diffusing across the polyethylene tetraphthalate bottle wall. Overall, the label claims made were defensible in terms of the best-before date, because it took at least 100 days of storage before the AA concentration in the most susceptible juices fell below the claimed value. This is because these drinks are fast moving consumer goods and storage beyond 100 days is unlikely. (Nonetheless, the supplier (Keri Juice Company) has since adopted its new unitised method of formulating juice. This has resulted in an initially higher concentration of vitamin C as compared to the juices under investigation.) In the nine months storage experiment there was some evidence for the presence of dehydroascorbic acid in blackcurrant drinks, but not in another three juices. Pasteurisation during preparation of these drinks resulted in up to 7 % loss of AA, probably due to oxygen dissolved in water, and accelerated by heat of pasteurisation. Higher temperatures in later storage also accelerated losses. Progressive exposure of juice to air during simulated consumption of 3 L bottles over a week also accelerated losses. Finally, exposure to sunlight in a diurnal temperature environment accelerated losses five-fold higher than in total darkness. Filtration of ultraviolet light approximately halved the loss due to sunlight. Overall however, it can be concluded that AA in the Keri range of juices is very resistant to degradation of AA.

Thesis (Ph.D.) -- University of Western Sydney, 2004. / A thesis presented to the University of Western Sydney, Centre for Advanced Food Research, in fulfilment of the requirements for the degree of Doctor of Philosophy in Advanced Food Science (& Food Packaging Science). Includes bibliography.

Thesis (Ph.D. (Physiology)) -- Mahidol University, 1978.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 162-178).

Made available in DSpace on 2014-06-11T19:23:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-16Bitstream added on 2014-06-13T19:29:44Z : No. of bitstreams: 1 pinto_mt_me_arafcf.pdf: 576726 bytes, checksum: a50426a4a05d15279f97ef78217293e9 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi realizar o estudo de vida-de-prateleira do suco de laranja concentrado e congelado avaliando suas características físico-químicas e sensoriais. Foi utilizado suco de laranja fresco, pasteurizado (104°C/10s) e concentrado, da variedade Pêra, da safra/04, fornecido por indústria produtora de suco de laranja da região de Araraquara, SP. A avaliação sensorial da cor, do aroma, do sabor e da impressão global do suco de laranja fresco, do suco pasteurizado e do suco concentrado foi realizada por uma equipe de 50 provadores utilizando teste de aceitação com escala hedônica estruturada de 9 pontos. Foram também determinados o teor de sólidos solúveis totais, o pH, a acidez total, o ratio, o teor de açúcares totais, de açúcares redutores, de ácido ascórbico e o conteúdo de hidroximetilfurfural. As análises foram realizadas logo após o processamento dos sucos - no tempo zero de estocagem - e durante a vida-de-prateleira do suco concentrado e congelado. O suco de laranja fresco apresentou as maiores notas de aceitação seguido do suco concentrado e do suco pasteurizado. O suco pasteurizado diferiu significativamente (p<0,05) dos demais em relação a todos os atributos avaliados, embora todos os sucos tenham apresentado aceitação sensorial superior à nota de corte. A aceitação de todos os atributos variou linearmente com o tempo de estocagem. O teor de sólidos solúveis totais dos sucos variou de 10,9 a 11,0°Bri x (p<0,05). A acidez total foi de 0,68 g ácido cítrico/100 mL para o suco de laranja fresco a 0,81 g ácido cítrico/100 mL para o suco concentrado (p<0,05). O ratio dos sucos variou entre 13,5 e 15,9 (p<0,05). O suco de laranja fresco apresentou pH 3,8 (p<0,05) e o maior teor de açúcares totais (9,0 g glicose/100 mL suco) (p<0,05). O suco de laranja pasteurizado apresentou o maior teor de açúcares redutores... / The aim of this work was to study the shelf life of frozen concentrated orange juice evaluating its physicochemical and sensory characteristics. Fresh orange juice, pasteurized orange juice (104°C/10s) and frozen con centrated orange juice of the Pera variety from the 2004 harvest were supplied by an orange juice industry in the Araraquara region, SP, Brazil. The sensorial evaluation of color, aroma, flavor and overall impression of the fresh, pasteurized and concentrated orange juice was carried out using a panel of 50 members, with a 9-point structured hedonic scale. Total soluble solids, pH, total acidity, ratio, total sugar, reducing sugar, ascorbic acid and hydroxymethylfurfural contents were also determined. The analyses were performed immediately after the juices were processed zero time of storage - and during the shelf life of the frozen concentrated orange juice. The fresh orange juice presented the highest acceptance scores, followed by the concentrated and the pasteurized juice. The pasteurized juice differed significantly (p<0.05) from the others with respect to all the attributes although all the juices showed sensorial acceptance higher than the cut off score. The acceptance of all the attributes varied linearly with storage. The total soluble solids of the juices varied from 10.9 to 11.0°Brix (p<0.05). Total acidi ty varied from 0.68 g citric acid/100 mL for the fresh orange juice to 0.81 g citric acid/100 mL for the concentrated juice (p<0.05). The ratio of the juices varied between 13.5 and 15.9 (p<0.05). The fresh orange juice showed pH 3.8 (p<0.05), the highest total sugar content (9.0 g glucose/100 mL juice) (p<0.05) and the highest ascorbic acid content (p<0.05), 66.7 mg/100 mL. The pasteurized orange juice showed the highest reducing sugar content (5.4 g glucose/100mL) (p<0.05)... (Complete abstract, click electronic address below)

Made available in DSpace on 2014-06-11T19:23:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-15Bitstream added on 2014-06-13T20:50:35Z : No. of bitstreams: 1 araujo_msp_me_arafcf.pdf: 1328537 bytes, checksum: 0953a2327131913e713b546c9116785b (MD5) / Universidade Estadual Paulista (UNESP) / Nesta pesquisa, foi avaliado o efeito da ingestão de 750 mL/ dia de suco de laranja sobre o perfil lipídico de 30 adultos de Araraquara, SP, Brasil. Essas pessoas foram divididas nos seguintes grupos: eutróficos, sem e com a suplementação dietética do suco de laranja e com excesso de peso, sem e com a suplementação do suco de laranja. Foram avaliados parâmetros antropométricos, dieta consumida e perfil lipídico. Não foram observadas variações nos parâmetros antropométricos em nenhum dos grupos. Entre as pessoas que fizeram suplementação dietética com suco de laranja, ocorreu diminuição na energia consumida (20%), no colesterol total dietético (42%), nos lipídeos totais (35%), nas proteínas totais (32%) e nos ácidos graxos saturados (30%) e um aumento do consumo de vitamina C (179%) e ácido fólico (43%). Nas pessoas que não fizeram a suplementação com o suco de laranja, o padrão dietético manteve-se inalterado. No grupo de pessoas eutróficas e no grupo de pessoas com excesso de peso, não suplementadas com suco, não ocorreram variações bioquímicas. Entretanto, nas pessoas com excesso de peso que fizeram suplementação dietética com suco de laranja, ocorreu aumento nos valores da glicemia de jejum (13%), da apo A1 (7%) e da apo B (6%), do HDL-c (8%) e da paraoxonase 1 (8%). Esses resultados são relevantes quanto ao papel protetor do suco de laranja contra aterosclerose e doenças cardiovasculares. / In this research, it was evaluated the effect of the regular consumption of orange juice on the lipid profile of 30 adults healthy or overweight, from Araraquara, SP, Brazil. They were divided in groups, that received or not 750 mL/day of orange juice. Antropometric and dietary variables and lipid profile had been evaluated. The supplementation of orange juice did not affected body mass index in none of groups. In group with orange juice supplementation, it was observed a reduction of the consumed energy (20%), cholesterol (42%), lipids (35%), proteins (32%) and saturated fatty acids (30%) and an increase of the vitamin C (179%) and folate (43%). In the group without orange juice supplementation, there were no changes in the dietary pattern. In the groups without overweight and in the group of people with overweight, not supplemented with orange juice, there were not noticed changes on lipids profiles. However, in the group of people with overweight who had with orange juice supplementation, increased serum glucose (13%), apo A1 (7%), apo B (6%), HDL-c (8%) and paraoxonase 1 (8%). Those results had shown the protective role of the orange juice preventing atherosclerosis and cardiovascular diseases.

Orientador: Katia Sivieri / Banca: Fernanda Lopes Kinouchi / Banca: Thais Borges Cesar / Resumo: Introdução: A microbiota intestinal se mantem em equilíbrio (homeostase) durante a fase adulta do ser humano, porém pode se desestabilizar através do estresse, tratamentos quimioterápicos, medicamentos e dietas. A homeostase pode ser alcançada através da ingestão de probióticos, prebióticos e componentes bioativos, tais como os flavonóides cítricos do tipo hesperitina e naringina. Objetivo: Avaliar o efeito da ingestão crônica de suco de laranja pasteurizado (POJ) sobre a microbiota intestinal das mulheres adultas. Material e métodos: foram avaliadas dez mulheres adultas, que ingeriram suco de laranja pasteurizado durante 60 dias, com um período de esmaecimento de 30 dias. As fezes foram coletadas antes da ingestão de suco de laranja (basal) e depois a cada 30 dias até o final do experimento, totalizando 120 dias do período experimental. Durante todo o período experimental, foi realizada a avaliação antropométrica de todos os indivíduos que participaram no estudo. Para a avaliação da microbiota intestinal, foram realizados análises microbiológicas dependente de cultivo usando meios seletivos para bactérias anaeróbias totais, Lactobacillus spp., Bifidobacterium spp. e Clostridium spp. Uma avaliação independente de cultura foi realizada usando a desnaturação Gradient Gel Electrophoresis (DGGE). Para a avaliação dos metabolismos microbiano foram realizadas as análises de pH, amónio (NH4 +) e ácidos graxos de cadeia curta (AGCC).Resultados: A ingestão crônica de suco de laranja n... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Introduction: The gut microbiota remains balanced (homeostasis) during the adult stage of the human being, but can be destabilized through stress, chemotherapeutic treatments, medicines and diets. Homeostasis can be achieved through ingestion of probiotic, prebiotic, and bioactive components such as hesperitin and naringin-type citrus flavonoids. Objective: To evaluate the effect of chronic ingestion of pasteurized orange juice (POJ) on the intestinal microbiota of adult women. Material and Methods: Ten adult women were evaluated, which ingested pasteurized orange juice during 60 days, with a washout period of 30 days. The stool was collected before orange juice intake (basal) and then every 30 days until the end of the experiment, totaling 120 days of experimental period. Throughout the experimental period, the anthropometric evaluation of all individuals who participated in the study was performed. For the evaluation of the intestinal microbiota, plate count analyzes were performed using selective media for total anaerobic bacteria, Lactobacillus spp., Bifidobacterium spp., and Clostridium spp. An independent culture evaluation was performed using Denaturing Gradient Gel Electrophoresis (DGGE). The pH, ammonium (NH4 +) and short chain fatty acids (SCFA) were evaluated for microbial metabolism. Results: Chronic intake of orange juice did not influence the body composition measurements but improved blood biochemical parameters. POJ showed positive modulations of the microbiota composition and metabolic activity. In particular, numbers of faecal Bifidobacterium spp and Lactobacillus spp were higher after 60 days of POJ intake. PCR-DGGE analysis showed that the microbiota of all the individuals studied had a similar composition in relation to total bacteria. In relation to the microbial metabolism, it was observed reduction of NH4+ values and increase (p≤0.05) in the production... (Complete abstract click electronic access below) / Mestre

Orientador: Magali Monteiro da Silva / Coorientador: Amauri Rosenthal / Banca: Roger Darros Barbosa / Banca: Rodrigo Rodrigues Petrus / Resumo: O suco de laranja é o suco de fruta mais popular e mais consumido em todo mundo. O Brasil é o maior produtor e exportador mundial de suco de laranja. O consumo de suco de laranja é estimado em mais de 9 bilhões de litros por ano, representando 47% do consumo mundial de suco. A fim de aumentar a vida de prateleira e a estabilidade do suco de laranja, a tecnologia de alta pressão hidrostática (APH) pode ser utilizada como um método alternativo à pasteurização. Este trabalho teve como objetivo otimizar as condições de processamento do suco de laranja da variedade Pêra Rio por APH, pressão (100- 600 MPa), temperatura (30-60 °C) e tempo (30-360 s), avaliar o efeito das condições do processamento de APH no ácido ascórbico e na atividade antioxidante do suco de laranja e avaliar a qualidade do suco de laranja processado a 520 MPa, 60 °C por 360 s, comparativamente ao suco pasteurizado e não processado. A metodologia de superfície de resposta foi empregada para estimar a redução da atividade da enzima pectinametilesterase (PME), da contagem de microrganismos, do ácido ascórbico e da atividade antioxidante no suco de laranja processado por APH. Também foram avaliados, as características físico-químicas, a cor instrumental, os compostos fenólicos e a atividade antioxidante do suco de laranja. O aumento da pressão, temperatura e tempo reduziram a atividade da PME e a contagem de microrganismos, exceto pela região entre 170 a 310 MPa, 30 a 45 °C e 30 a 150 s, que aumentou a atividade da PME. A faixa ótima de processamento por APH foi 550 a 600 MPa, 55 a 60 °C e 330 a 360 s, sendo capaz de produzir suco de laranja com população de microrganismos de menos de 2 ciclos logarítmicos de UFC/mL e atividade residual da PME menor que 20%. Ainda, o aumento da temperature e do tempo do processamento por APH reduziu o teor de ácido ascórbico... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Orange juice is the most popular and consumed fruit juice in the world. Brazil is the main orange juice world producer and exporter. The consumption of orange juice is estimated at more than 9 billion liters per year, which represents 47% of global fruit juice consumption. In order to improve orange juice shelf life and stability, high hydrostatic pressure (HHP) processing can be used as an alternative to pasteurization. The aim of this work was to optimize the HHP processing conditions of Pêra Rio orange juice, namely pressure (100-600 MPa), temperature (30-60 °C) and time (30-360 s), to evaluate the effect of HHP processing conditions on ascorbic acid and antioxidant activity of orange juice and to evaluate the quality of orange juice processed at 520 MPa, 60 °C for 260 s in comparison to pasteurized and non processed orange juice. Response surface methodology was used to estimate the decrease of microflora, pectinmethyl esterase (PME) activity, ascorbic acid and antioxidant activity in HHP processed Pêra Rio orange juice. The physicalchemical characteristics, the instrumental color, the total phenolic compounds and the antioxidant activity of orange juice were also evaluate. The increase in pressure, temperature and time reduced the PME activity and native microflora of orange juice, except at the region between 170 to 310 MPa, 30 to 45 °C and 30 to 150 s, which enhanced PME activity. The range of optimum HHP processing conditions were 550 to 600 MPa, 55 to 60 °C and 330 to 360 s, which was able to produce a stable orange juice with microorganisms population less than 2 log cycles CFU/mL and PME residual activity less than 20%. The increase in time and temperature of HHP exert influence on the reduction of ascorbic acid and antioxidant activity on orange juice... (Complete abstract click electronic access below) / Mestre

The object of the study was a sensory evaluation of used sweetners in beverages from selected fruits. Within the sensory analysis apple juice and also pear, apricot, cherry and blackcurrant nectar were used. These drinks were subsequently diluted at two concentrations with drinking water: 1) in a ratio of 50 % of the original beverage and 50 % of drinking water; 2) in a ratio of 25 % of the original beverage and 75% of drinking water. Each of the concentrations were then divided into groups which were sweetened with white sugar, cane sugar, aspartame, sucralose or rebaudioside A. The performed sensory analyses show that rebaudioside A would have great potential to replace the commonly used white sugar in apple juice. Sucralose would have this potential in pear and cherry drinks. However, the use of other sweeteners in other types of beverages is also not excluded, because to prove a preference for white sugar failed in most cases.

126f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-03-22T15:11:05Z No. of bitstreams: 1 Tese_Lidércia.pdf: 1854558 bytes, checksum: 7d54dd03b3bb8154f1ce2f0564633c7d (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-04-19T13:36:52Z (GMT) No. of bitstreams: 1 Tese_Lidércia.pdf: 1854558 bytes, checksum: 7d54dd03b3bb8154f1ce2f0564633c7d (MD5) / Made available in DSpace on 2013-04-19T13:36:52Z (GMT). No. of bitstreams: 1 Tese_Lidércia.pdf: 1854558 bytes, checksum: 7d54dd03b3bb8154f1ce2f0564633c7d (MD5) Previous issue date: 2009 / CAPES / Este trabalho foi desenvolvido no âmbito do PRONEX – NQA e descreve o estudo através da técnica da Cromatografia Líquida de Alta Eficiência acoplada a detector de arranjo de diodos - CLAE-DAD nas análises de amostras de sucos de laranja obtidos por processos extrativos diversificados (espremidos a mão, extração em condições industriais com posterior comercialização em longo prazo e obtido através de máquinas tipo fresh-in-squeeze) para a identificação de flavonóides e psoraleno. Os diversos sucos foram submetidos às etapas de extração líquido-líquido e posterior análises por CLAE-DAD. Estes procedimentos permitiram identificar e quantificar algumas flavanonas e psoraleno presentes nos sucos cítricos. Dentre as flavanonas se determinou hesperidina, naringina, naringenina e poncirina. As faixas de concentrações destes compostos variaram de 17,8 - 245 mg 100 g-1 para hesperidina, 0,01 – 0,08 mg 100 g-1 para naringina, 0,05 – 0,170 mg 100 g-1 para naringenina e de 0,06 – 0,36 mg 100 g-1 para poncirina. Quanto ao psoraleno, em algumas amostras dos sucos, as concentrações estavam abaixo do limite de quantificação (< 0,02) e variou de < 0,02 – 0,05 mg 100 g-1. Estes resultados sugerem que o modo de obtenção dos sucos e os critérios de extração dos constituintes podem influenciar tanto nos teores dos flavonóides no suco como nas detecções de suas concentrações através da técnica aplicada. Para exames das informações geradas foram empregadas metodologias estatísticas multivariadas por meio de Análises de Componentes Principais (PCA) e Análise de Agrupamentos Hierárquicos (HCA) executando o estudo exploratório dos dados para avaliar tendências e discriminar amostras dos sucos de laranja quanto a sua origem, tipos de tratamentos de extração e características químicas para os teores de flavonóides e psoraleno. / Salvador