Soluble Pectin Content Research Articles

High-pressure treatment of cloudy apple juice

A factorial design with four factors (pressure, holding time, temperature and waiting period between crushing of apple and high-pressure (HP) treatment) was built up to study the effect of HP treatment on pectin methylesterase activity (PME, EC 3.1.1.11) in cloudy apple juice. PME activity was measured by the methanol release during the storage of samples at 4 °C for 1 month. Only the holding time of the treatment and three interactions between factors (holding time×temperature, pressure×waiting and holding time×waiting) had significant effects on the PME level. Increasing the pressure or the holding time at moderate temperatures (15–40 °C) increased the activity. PME purified from apple was pressure stable in the range 100–600 MPa at 25 °C. The soluble pectin content was not changed after HP treatment. The particles size increased with the temperature reached during the treatment, in agreement with a diffusion-limited-aggregation model but were independent of pressure and holding time. In a separate experiment we found a positive correlation between the PME activity and the residual content of the catechins suggesting that polyphenoloxidase (PPO, EC 1.14.18.1) and oxidized polyphenols play a role in the PME activity level after HP treatment.

Evaluation of pectin constituents of Japanese pear by near infrared spectroscopy

Japanese pears ( Pyrus serotina Rehder var. culta ‘Housui’) collected in 1997 and 1998 were measured for their pectin constituents including alcohol insoluble solids, water soluble pectin, oxalate soluble pectin, non-soluble pectin and total pectin. Near infrared (NIR) spectra (1100–2500 nm) were measured within the range of at 2 nm intervals. The NIR spectra of intact Japanese pear were measured by fiber optics in interactance mode and the spectra of juice were measured by diffuse trans-reflectance. The spectral data used were raw spectra and their second derivative. By using multiple linear regression, calibration equations developed from the intact fruit spectra and juice spectra, the alcohol insoluble solids in the fresh weight (AIS in the FW) and the oxalate soluble pectin content in the alcohol insoluble solids (OSP in the AIS) were accurately predicted (For intact fruit spectra: R = 0.93, SEP = 0.62 for AIS in the FW, and R = 0.95, SEP = 8.48 for OSP in the AIS; For juice spectra: R = 0.93, SEP = 0.63 for AIS in the FW and R = 0.91, SEP = 7.93 for OSP in the FW). In addition, the equations from the juice spectra could be used to predict the water soluble pectin in the alcohol insoluble solids (WSP in the AIS), and the total pectin in the alcohol insoluble solids (TP in the AIS) ( R = 0.91, SEP = 1.41 for WSP in the AIS and R = 0.94, SEP = 11.52 for TP in the AIS). The NIR models developed with the data collected in 1998 were not able to predict the 1997 data. This study showed that near infrared spectroscopy has potential to measure the pectin constituents of the Japanese pear.

PHYSIOLOGICAL CHANGES OF RADISH (RAPHANUS SATIVUS L.) IN POSTHARVEST AS AFFECTED BY PREHARVEST CLIMATE CONDITIONS

The quality characteristics of radish are influenced by the product's precondition, which are determined by the climate conditions during the production process. Postharvest packaging treatments could not prevent undesired physiological changes within five days of storage. This effect could be caused by the enhanced respiration rate of these radishes which were grown under higher temperature and irradiation rates resulting in a higher growth rate and thus higher respiration rate leading to an acceleration of the consumption of primary respiration substrates like glucose and fructose and marked by a distinct decomposition of sucrose. A modification of the internal atmosphere in starch coated radish roots - caused by an additional physical barrier - might not have been strong enough to prevent the degradation of sucrose due to a suppressed respiration. The decomposition of sucrose was also observed in OPP-film and foodtainer packaging. Foodtainer packaging and OPP-film wrapping maintained the soluble and insoluble pectin content independently of the radish precondition leading to an unchanged root firmness with the exception of progressed developed radishes. In contrast, starch coated radishes caused a decrease in root firmness. Maintaining alkenyl glucosinolates strongly depend on the product's precondition. All three postharvest treatments prevented undesired postharvest colour changes independently of the radish precondition.

Suculência e solubilização de pectinas em maçãs ‘Gala’, armazenadas em atmosfera controlada, em dois níveis de umidade relativa

O objetivo deste trabalho foi o de avaliar o efeito de umidades relativas (UR) de 96 e 90%, em maçãs ‘Gala’ armazenadas por 8 meses em atmosfera controlada (AC) sobre a perda de suculência, firmeza de polpa, conteúdo de pectina solúvel (PS) e atividade das enzimas pectinametilesterase (PME) e poligalacturonase (PG). A temperatura de armazenamento em AC foi de 0,5°C. Ao final do período em AC e mais 7 dias a 20°C, foram avaliadas a suculência, a firmeza de polpa, o conteúdo de PS e as atividades da PME e PG. A UR na faixa de 96 a 90% não afetou a suculência, a firmeza, o conteúdo de PS e a atividade da PME, mas em 90% de UR ocorreu aumento da atividade da PG, após 8 meses em AC e mais 7 dias a 20°C.

Componentes de parede celular de grãos de frutos de café (Coffea arábica L.) submetidos a diferentes tempos à espera da secagem

Traditionally it is recommended the transport and spreading of the coffee from the crop place to the drying place the fastest possible, never leaving him heaped. However this technical recommendation lacks scientific data that justify her. This way, Coffees (Coffea Arabica L.) of the cultivar Catuaí vermelho were harvested in July 1 1998 in Carmo do Rio Claro region in Minas Gerais state where berries of a same plot, containing, on average, 53.89% of cherry, 23.14% dry/overipe and 22.96% of immature berries were utilized After harvested, the berries were separated into batches of 180 liters of berries for each waiting time and divided into three replicates of 60 liters of berries each one; those berries were bagged into polyethylene plaited bags and arranged on the flat for different times, ranging in 0,1,2,3,4,5,6 and 7 days, afterwards, drying was proceeded on the flat itself till the beans reached from 11 to 13% of moisture. Next, a enough amount of sample was withdrawn for chemical analyses. Indefinite variations occurred in the contents of soluble pectin, neutral detergent fiber, acid detergent fiber, lignin, hemicellulose, cellulose, pectinmethylesterase and polygalacturonase activity and not varying total pectin and pectin solubility, showing that there is no significant damage in bean cell wall structuration from the moment the bagged berries are maintained for different times waiting for drying

Effect of some operational extrusion parameters on the constituents of orange pulp

Orange pulp was extruded using a Brabender laboratory single screw extruder (20:1 L/D), with the objective of modifying the properties of the fibre components. Response surface methodology was used following a central rotational composite, experimental design (5 3). The independent variables studied were: barrel temperatures (83, 100, 125, 150, and 167 °C); moisture contents (22%, 25%, 30%, 35% and 38%) and screw speed (126, 140, 160, 180 and 190 rpm). The feed speed was kept constant (70 g/min). The compression ratio was 3:1, and the diameter of the die 4 mm. The extrusion process decreased insoluble dietary fibre in 39.06% and soluble dietary fibre was increased by 80%. Also, total dietary fibre was decreased as consequence of the production of smaller fragments that would not be completely recovered during the alcoholic precipitation. Increments in contents of total pectin and soluble pectin resulted from the solubilization of pectic substances.

Avaliação da suculência e da solubilização de pectinas em maçãs 'gala' armazenadas em atmosfera controlada, em função de diferentes pressões parciais de O2 e CO2

Objetivou-se com este trabalho avaliar o efeito de pressões parciais de O2 e CO2 (1,0 kPa+2,5 kPa, 1,0 kPa+2,0 kPa, 0,8 kPa+2,0 kPa, 0,8 kPa+2,5 kPa e 20,8 kPa+0,03 kPa, respectivamente) em maçãs `Gala´ (Malus domestica Baumg.) armazenadas por 8 meses em atmosfera controlada (AC) sobre a perda de suculência, firmeza de polpa, conteúdo de pectina solúvel (PS) e atividade das enzimas pectinametilesterase (PME) e poligalacturonase (PG). A temperatura de armazenamento foi de 0,5°C e umidade relativa do ar, em torno de 96%. Ao final do período em AC e mais 7 dias a 20°C, foram avaliadas a suculência, firmeza de polpa, conteúdo de PS e atividades da PME e PG. As pressões parciais de 1,0 kPa de O2 + 2,0 kPa de CO2 e 0,8 kPa de O2 + 2,0 kPa de CO2 conferiram maior suculência após 8 meses em AC; e as maçãs mais firmes foram as mais suculentas, independente da concentração da atmosfera.

Textura de goiabas "Pedro Sato" submetidas à aplicação de cloreto de cálcio

Entre as técnicas utilizadas para manter a qualidade pós-colheita de frutos, destaca-se a aplicação de cálcio, geralmente associada à refrigeração. No entanto, nem todos os produtores têm acesso a câmaras frias; portanto, objetivou-se neste trabalho avaliar o tratamento isolado com cloreto de cálcio na manutenção da aparência de goiabas (Psidium guajava L.) destinadas ao consumo “in natura”, armazenadas em condições ambientes. O tratamento hidrotérmico à temperatura de 30ºC com cloreto de cálcio a 1g/100 mL (CCa) foi testado, comparando-o com frutos sem tratamento (SCa). Em seguida, os frutos foram armazenadas em condições ambientes (22,6ºC ± 1, UR 75% ± 5) durante quatro dias. Após o armazenamento, avaliaram-se os teores de pectina total e solúvel e as atividades de pectinametilesterase e poligalacturonase. O emprego de cálcio afetou as características analisadas, proporcionando menores teores de pectina solúvel e atividades mais baixas de pectinametilesterase e poligalacturonase, promovendo um amaciamento menos intenso e mantendo a firmeza desses frutos durante o período de armazenamento.

Regulation of 1-MCP-Treated Banana Fruit Quality by Exogenous Ethylene and Temperature

Ripe green banana (Musa sp., AAA group, cv. Zhonggang) fruits treated with 1-methylcyclopropene (1-MCP) significantly delayed the peaks of respiration rate and ethylene production but did not reduce the peak height. Mature banana fruits were also treated with 1-MCP for 24 h at 20 C and then exposed to 50 mL/L ethylene or stored at different temperatures to analyse the effects of external added ethylene. Reductions in firmness, titratable acidity (TA) and starch content (SC) of banana fruits were remarkably delayed by 1-MCP treatment. 1-MCP treatment also delayed the increase of total soluble sugar (TSS) and soluble pectin (SP) contents. Soluble solids (SS) content in the 1-MCP-treated fruit remained almost unchanged during the first 10 days of storage at 20 C. No significant differences in TA, TSS, SP and SS levels were observed between the fruit treated with 1-MCP alone and the fruit treated with 1-MCP plus ethylene. The 1-MCP effects on all the parameters related to banana ripening were enhanced by low temperature storage and reduced by high temperature storage.

The effects of gamma irradiation on the microbiological, physical and sensory qualities of diced tomatoes

Diced Roma tomatoes were treated with gamma irradiation and evaluated for changes in microbial, physical, chemical and sensory properties. Dosages for Trial 1 were 0.0, 0.39, 0.56 and 1.82 kGy and in Trial 2, 0.0, 0.50, 1.24 and 3.70 kGy. Irradiation at 3.70 kGy resulted in no aerobic populations through day 12 and significantly fewer colonies through day 15 whereas yeast and mold populations experienced a 2 log reduction through day 12. Color, titratable acidity, and °Brix were not significantly affected by irradiation. Tissue firmness decreased with increasing dose but not with storage time. Treatment with 3.7 kGy decreased firmness by 50% and 20% with 0.5 kGy, however, the reduced firmness induced by 0.50 kGy was undetected by a 9 member trained sensory panel. A significant ( p⩽0.05) inverse correlation between changes in texture and water-soluble pectin (WSP) was determined while total pectin remained relatively constant and oxalate soluble pectin content decreased slightly with irradiation dose. The significant inverse correlation between the loss of firmness and WSP indicates that the changes in WSP play an important role in the tissue softening of tomatoes, This study indicates that irradiation at 0.5 kGy can reduce microbial counts substantially to improve microbial shelf life without adverse effects on sensory qualities.

Effect of Cloud Particle Characteristics on the Viscosity of Cloudy Apple Juice

ABSTRACT: Particle size, shape, and volume fraction as well as soluble pectin content and electro‐viscous effects on cloudy apple juice viscosity were investigated. Particle characteristics were micrographically determined by electron microscopy. More than 2300 particles were digitalized and statistically analyzed. Cloudy apple juice resulted in a suspension of irregular shape particles ranging from 0.25 to 5 μm in size. A 10 °Brix juice had a particle volume fraction of φ0= 3.93 ∞ 10‐3. Relative viscosity values were fitted to the generalized Sudduth equation. Intrinsic viscosity resulted 5.8 times greater than the theoretical value predicted by Einstein (α= 2.5). This was attributed to the first electro‐viscous effect. Results also indicate that the effect of particle non‐sphericity on cloudy apple juice viscosity can be neglected. Soluble pectin was found to increase juice viscosity significantly. Combined effects result in a strong linear increase of relative viscosity.

PHYSICOCHEMICAL FACTORS AFFECTING FIRMNESS OF PASTEURIZED JALAPENO PEPPER RINGS

ABSTRACTPhysical and chemical properties that influence textural properties of pasteurized pepper rings of four jalapeno pepper cultivars were determined. Hardness, cohesiveness, gumminess and chewiness were positively correlated with moisture and wall thickness, and negatively associated with water soluble pectin and alcohol insoluble solid (AIS) contents. After 90 days' storage, Veracruz peppers were firmer than the other cultivars due to their greater levels of chelator soluble pectin and bound calcium, and lower levels of water soluble pectin. Texture measurement of fresh peppers was not a reliable predictor of firmness for pasteurized peppers.

TEXTURA DE FEIJÃO-VAGEM (Phaseolus vulgaris L) PROCESSADO OU NÃO: EFEITO DA APLICAÇÃO DE CONCENTRAÇÕES CRESCENTES DE CÁLCIO VIA ABSORÇÃO RADICULAR

Esta investigação teve como objetivo estudar o efeito do cultivo de feijão-vagem com doses crescentes de cálcio na textura das vagens antes e após processo de enlatamento. O experimento foi desenvolvido com a cultivar UEL 1, utilizando-se areia grossa como substrato. Os tratamentos constaram das seguintes concentrações de cálcio em solução nutritiva: 0, 75, 150 e 300 ppm. Foram determinados os teores de cálcio das vagens in natura, substâncias pécticas e textura das vagens in natura e processada. As concentrações de cálcio nas vagens aumentaram em paralelo à elevação dos níveis de cálcio adicionados à solução nutritiva. Os teores de pectina solúvel nas vagens in natura não diferiram entre os tratamentos. Houve um acréscimo da quantidade de pectina insolúvel em função do aumento das doses de cálcio. Após o processamento térmico ocorreu uma solubilização das pectinas. A maior concentração de pectina solúvel nas vagens enlatadas foi observada nas vagens cultivadas sem adição de cálcio na solução nutritiva. As medidas de textura demonstraram uma tendência de aumento de firmeza das vagens concomitante à elevação nos teores de cálcio antes e após o processo de enlatamento.

Effect of 100% CO2 treatment for keeping quality of strawberry fruits

'Hokowase' strawberries (Fragaria ananassa DuCH) were treated with 100% CO2 at 25°C for 0, 3, 6, 12, 18 or 24 hr. The flesh firmness of fruit increased for all CO2 treatments tested. The 6 hours treatment was the most suitable duration for maintaining quality of the fruit, because a long time treatment caused severe browning of sepal and an off-flavor of the fruit. The fruit which was stored 0, 24 or 48 hr. after harvest were treated with 100% CO2 for 6 hr. The delayed treatment, 24 hr. and 48 hr. after harvest, was more effective for increasing firmness and prevention of decay than non-treatment. The fruit were treated with 100% CO2 or N2 for 24 hr. CO2 treatment resulted in firmer fruit and a decrease of the ratio of water soluble pectin content and an increase of hexametaphosphate soluble pectin, while N2 treatment did not affect texture or pectin substances.

The Mechanism of the Increase of Firmness in Strawberry Fruit Treated with 100% CO2.

In this paper, we studied the mechanism of the increase of firmness in strawberry fruit treated with 100% CO2. Internal CO2 concentration in treated fruit increased immediately after the treatment and maintained the high level during treatment. But, it decreased rapidly after release of the treatment and reached the same level of untreated ones. This treatment rapidly decreased the ratio of water soluble pectin content against total pectin content and increased the ratio of hexametaphosphate soluble pectin content during and after the treatment, but did not affect the ratio of hydrochloric acid soluble pectin to total pectin in the fruit. Pectin methyl esterase activity was higher in treated fruit than the one in untreated fruit during and after the treatment. The ratio of Ca content of NaCl-soluble fraction (contained pectin substances) to total Ca content was higher in the treated fruit during and after treatment than the one in untreated fruit. These results suggest that the increase of firmness of strawberry fruit by 100% CO2 treatment may be due to the formation of intramolecular bridges in pectin, mediated by Ca2+

EFFECTS OF SHORT TERM CA STORAGE ON PEACH QUALITY

Mature, unripe peaches were stored at 1°C in air or in 1% O2 plus 2.5%, 5.01, or 10.0% CO2 for 25 days and then ripened in air at 15°C for 3 days. Fruit stored in air or 2.5% CO2 developed browning of the flesh during ripening but fruit stored in 5.0% or 10.0% CO2 turned yellow. Only the fruit stored in 10.0% CO2 softened during ripening, but water soluble pectin content increased and protopectin content decreased in peaches stored in 5.0% or 10.0% CO2. Low temperature storage apparently interferes with the levels and/or activities of the pectin degrading enzymes during subsequent ripening of peaches. High levels of CO2 during low temperature storage appears to reduce chilling injury by protecting the capacity of the fruit to produce adequate levels of the pectolytic enzymes at ripening temperatures.

Chemical and Physical Changes in Beet (Beta vulgaris L.) Root Tissue During Simulated Processing–Relevance to the “Black Ring” Defect in Canned Beets

ABSTRACTPreheating slices of beet root tissue at 40 to 60°C led to a loss in tissue integrity indicated by higher leakage of electrolytes and endogenous pigments, and increases in water soluble pectin content. When tissue slices were incubated at 25°C for 1 hr after preheating at 50 to 60°C, reducing sugar increased. Incubation after preheating at 40 to 60°C resulted in decreased phenolic acid content. Endogenous poly‐phenoloxidase and peroxidase retained about 50% of their original activity after preheating for 5 min at 70 and 60°C, respectively. These results bear relevance on the occurrence of the “black ring” defect in canned beets.

Maturity evaluation of kiwifruit determined on the basis of starch and pectin contents and related enzyme activities.

Since it is difficult to judge maturity of kiwifruit by appearance, growers measure the soluble solids (S.S.) content using a refractometer. In order to find a suitable harvest index other than S.S. and firmness, starch content, total pectin (TP) and water soluble pectin (WSP) contents, β-amylase and polygalacturonase (PG) activities of kiwifruit were investigated. The S.S. content, measured with a refractometer, and firmness of kiwifruit stored at room temperature (20°C), with or without ethylene treatment were compared. Kiwifruit treated with ethylene after harvest showed more uniform firmness and S.S. content than those without ethylene treatment. β-Amylase and PG activities, TP and WSP contents could not be used as alternative harvest and shipment indices for kiwifruit owing to fluctuation in their values. The use of S.S. content as a maturity index appeared to be applicable in 'Hayward' but not in the early-ripening cv. Koryoku. If 'Koryoku' were to be harvested based on the optimum S.S. content, the fruit would have to be shipped within 2 days after ethylene treatment to maintain suitable firmness. In 'Koryoku', the period of highest starch content is a better maturity index than S.S. content. Harvesting at the suitable period would ensure longer storage and maintenance of firmness and sweetness.

Cuticular Properties and Postharvest Calcium Applications Influence Cracking of Sweet Cherries

Abstract The influence of stomata, the stylar scar, cuticular fractures, and Ca2+ on susceptibility of ‘Bing’ sweet cherry fruit (Prunus avium L.) to water injury was studied. Water injury was first detected as an increase in cell turgor. Water penetration caused separation of the cuticle from the epidermal cell wall. Swelling in the epidermal cell wall region resulted in cuticular fracturing that generally preceded fruit cracking. Uncracked fruit that had cuticular fractures softened rapidly. Stomata were sparsely distributed on the fruit surface and were often fixed in an open or partially open position. Water injury was not visible at stomata even when injury occurred adjacent to the stomatal region. Initial signs of injury were commonly visible near the stylar scar. Histochemical studies revealed that the surface of the stylar scar was devoid of a cuticle covering and was rich in insoluble carbohydrates. Greater penetration of solute containing 45Ca2+ occurred at the stylar scar. Fine fractures in the cuticle surface were observed in fruit at harvest time in 1985 and 1986. Cherry fruit with cuticular fractures had a higher water absorption rate than unfractured fruit. In immersion tests, Ca2+ reduced cherry cracking. EGTA increased fruit cracking; this increase was negated by adding Ca2+. Neither Ca2+ nor EGTA affected the water absorption rate of the fruit. EGTA decreased the cracking threshold of the fruit, while Ca2+ increased it. Soluble pectin content of the immersion solution rose with increasing incubation times. EGTA increased while Ca2+ markedly decreased soluble pectin concentration in the immersion solution. Histochemical studies indicated a breakdown of the cell wall structure in the epidermal region of water-injured fruit. Autoradiographs of fruit immersed in a solution containing 45Ca2+ showed the epidermal region to be the site of Ca2+ action in altering fruit cracking. Chemical name used: Ethyleneglycol-bis-(β-aminoethyl ether) N,N,N,N-tetraacetic acid (EGTA)

Canning Quality Evaluation of Pinto and Navy Beans

ABSTRACTThermal processing of pinto and navy beans at 121.1°C for 16 or 14 min in a still retort gave similar sterilization value (Fo= 10) as the processing at 115.6°C for 45 min. The 121.1°C/16 or 14 min process produced beans with greater firmness than the 115.6°C/45 min process. The addition of CaCl2 and EDTA improved firmness and color of canned beans. Calcium chloride also reduced clumping and splitting of the canned beans. Sensory evaluation showed that the acceptability of canned beans was reduced when CaCl2 was increased up to 10 mM. High correlation between firmness and soluble pectin in various bean cultivars implied that soluble pectin content could be used as a parameter for screening bean cultivars with desirable firmness.