Physiological changes during postharvest senescence of broccoli

The objective of this work was to determine the early physiological changes throughout shelf life of fresh broccoli (Brassica oleracea L. var. italica) cv. Piracicaba Precoce at 25ºC and relative humidity of 96% in the dark until complete senescence. Head inflorescences showed lack of turgidity and commercial value when weight loss reached up to 5%, coinciding with 48 hour after harvest. Chlorophyll content was stable until 24 hours after harvesting; afterwards, an intense degradation phase took place. At 72 hours, total head yellowing was observed when chlorophyll content dropped to 30% of its initial content. Peroxidase activity increased by 1.4 fold during the first six hours, dropping to its lowest level approximately 24 hours after harvesting. However, from this time on, an increment of activity was observed until 72 hours. At 24 hours after harvesting, respiration was reduced by 50%. At later stages of senescence, respiration of florets was stable, but in a lower level than that determined at harvest. Sharp reduction of starch and reducing sugars was observed within 24 hours after harvesting, followed by continuous period of decline in starch and non-reducing sugars.

Ripening and quality of 'Laetitia' plums following harvest and cold storage as affected by inhibition of ethylene action

The inhibition of ethylene action by 1-methylcyclopropene (1-MCP) extends shelf and storage life of many climacteric fruits. However, 1-MCP appears to have limited effects on stone fruit depending on specie and cultivar. The effects of 1-MCP on ripening and quality of 'Laetitia' plums were determined during ripening at 23ºC following harvest and cold storage. Japanese plums (Prunus salicina, cv. Laetitia) were harvested at mature pre-climacteric stage, cooled to 2ºC within 36 hours of harvest and then treated with 0, 0.05, 0.10, 0.50 or 1.00 muL L-1 of 1-MCP at 1°C for 24 hours. Following treatment, fruits were either held at 23ºC for 16 days or stored at 1ºC for 50 days. Fruits were removed from cold storage at 10-day intervals and allowed to ripe at 23°C for five days. A delay of climacteric respiration and ethylene production by 1-MCP treatment during ripening following harvest and cold storage was associated to a slow rate of fruit softening. 1-MCP treatment also delayed the loss of titratable acidity and changes of flesh and skin color, whereas it had little or no effect on soluble solids content. 1-MCP effects were concentration- and storage duration-dependent and, generally, a saturation fruit response to 1-MCP occurred between 0.5 and 1.0 muL L-1. During ripening, 1-MCP treated fruits attained quality similar to that of controls. Results indicated that 1-MCP treatment may extend shelf life (23ºC) and storage life (1ºC) of 'Laetitia' plums by approximately six and 20 days, respectively.

High-pressure processing and antimicrobial biodegradable packaging to control Listeria monocytogenes during storage of cooked ham

The efficiency of combining high-pressure processing (HPP) and active packaging technologies to control Listeria monocytogenes growth during the shelf life of artificially inoculated cooked ham was assessed. Three lots of cooked ham were prepared: control, packaging with alginate films, and packaging with antimicrobial alginate films containing enterocins. After packaging, half of the samples were pressurized. Sliced cooked ham stored at 6 °C experienced a quick growth of L. monocytogenes. Both antimicrobial packaging and pressurization delayed the growth of the pathogen. However, at 6 °C the combination of antimicrobial packaging and HPP was necessary to achieve a reduction of inoculated levels without recovery during 60 days of storage. Further storage at 6 °C of pressurized antimicrobial packed cooked ham resulted in L. monocytogenes levels below the detection limit (day 90). On the other hand, storage at 1 °C controlled the growth of the pathogen until day 39 in non-pressurized ham, while antimicrobial packaging and storage at 1 °C exerted a bacteriostatic effect for 60 days. All HPP lots stored at 1 °C led to counts <100 CFU/g at day 60. Similar results were observed when combining both technologies. After a cold chain break no growth of L. monocytogenes was observed in pressurized ham packed with antimicrobial films, showing the efficiency of combining both technologies.

Active packaging containing nisin and high pressure processing as post-processing listericidal treatments for convenience fermented sausages

Listeria monocytogenes was inoculated on the surface of sliced fermented sausages with no added sodium salt. The pathogen was progressively inactivated during the product shelf life (90 days). Antimicrobial packaging of fermented sausages with PVOH films containing nisin induced a more pronounced reduction of L. monocytogenes counts during refrigerated storage. HPP alone (600 MPa, 5 min, 12 °C) had no antimicrobial effect against L. monocytogenes at the studied conditions. Combination of HPP with antimicrobial packaging did not produce any extra protection against L. monocytogenes compared to antimicrobial packaging alone. The lack of effect of HPP on L. monocytogenes was attributed to a protective effect exerted by the low water activity of the product and its lactate content. These results reflect that antimicrobial packaging with the inclusion of nisin as a natural antimicrobial could be considered as an effective method to reduce the levels of L. monocytogenes in sliced fermented sausages with no added sodium salt

Conservation of 'Pedro Sato' guavas under treatment with 1-methylcyclopropene

The search for techniques that extend shelf life of guava (Psidium guajava) fruits, and reduce its postharvest losses is desirable. The objective of this work was to evaluate the effects of concentrations of competitive ethylene antagonist 1-methylcyclopropene (1-MCP) on conservation of 'Pedro Sato' guava fruits. Treatments consisted of 0, 100, 300 or 900 nL L-1 of 1-MCP for 3 hours followed by storage at 25ºC, and 10ºC with 90±5% RH. The application of 900 nL L-1 1-MCP for 3 hours was efficient in delaying loss of skin color, and in keeping fruit firmness at both storage temperatures. The 300 nL L-1 of 1-MCP concentration was efficient in delaying skin color loss only when fruits were stored at 10ºC. The effect of 1-MCP was quite significant on the reduction of rot incidence at both storage temperatures. The respiratory rate was lower in fruits treated with 300 and 900 nL L-1 of 1-MCP during storage at 25ºC. The product was efficient in delaying the ripening of fruits, and the concentration of 900 nL L-1 showed the best effect.

Application of 1-methylcyclopropene, calcium chloride and calcium amino acid chelate on fresh-cut cantaloupe muskmelon

The objective of this work was to determine the effects of postharvest application of 1-methylcyclopropene (1-MCP) and two calcium salts, applied individually or combined, on firmness and visual quality of fresh-cut muskmelon stored in air, for 18 days. Two sets of fruits, one of them exposed to 1-MCP at 300 nL L-1, were cut into cubes, dipped in deionized water, or in 1% Ca solutions as CaCl2, or in calcium amino acid chelate (Ca-chelate), placed in clamshell containers, and stored in air at 5±1ºC and 90±5% RH, for 18 days. The assay was conducted using an entirely randomized design, with three replications, in a split plot array. Evaluation of visual appearance, color, flesh firmness, total soluble solids, titratable acidity, and pH was performed right after treatments, and every period of three days, up to eighteen days. Application of 1-MCP at 300 nL L-1, calcium chloride or Ca-chelate, or the combination 1-MCP and calcium, preserved initial freshness and reduced softening of the samples. Ca-chelate synergistically enhanced the effect of 1-MCP on firmness after nine days of storage, while calcium chloride improved firmness of the samples throughout storage. Ca-chelate may serve as an alternative for shelf life extension of cantaloupe fresh-cut muskmelon.

Potassium permanganate effects in postharvest conservation of the papaya cultivar Sunrise Golden

The objective of this work was to evaluate the effects of KMnO4 on the extension of postharvest life of 'Sunrise Golden' papaya, stored under modified atmosphere and refrigeration. Fruit with up to 10% yellow peel were harvested in a commercial orchard in Linhares, state of Espírito Santo, Brazil. Sets of three fruit (unit mass of 289.9±18.5 g) were wrapped in low-density polyethylene films (28 ¼m thick) containing sachets of KMnO4 at 0, 0.5, 1, 1.5, and 2 g per bag. The bags were sealed and stored at 10.4±0.9°C and 90±5% relative humidity for 25 days. After this period, the fruit were removed from the bags and maintained at 21±0.8°C and 90±5% relative humidity until complete ripening. Four days after bag sealing, CO2 concentration stabilized in all treatments, and was higher in bags without KMnO4. In all treatments, fruit reached the climacteric respiratory peak on the third day after bag removal, coinciding with peel color index of 3.5. Increasing the KMnO4 dose reduced the losses in fruit fresh matter, consistency and pulp electrolyte leakage. Potassium permanganate was effective in maintaining the fruit at the pre-climacteric stage during the 25-day storage, and did not interfere with normal ripening after bag removal.

'Royal Gala' apple quality stored under ultralow oxygen concentration and low temperature conditions

The objective of this work was to evaluate the interaction of ultralow oxygen concentrations (ULO) with storage temperatures and carbon dioxide partial pressures and its influence on fruit quality preservation and on the occurrence of physiological disorders in 'Royal Gala' apples. The experiment was carried out in a completely randomized design, with four replicates 25-fruit. ULO conditions (1.0 kPa O2 + 2.0 kPa CO2; 0.8 kPa O2 + 1.5 kPa CO2; 0.8 kPa O2 + 1.0 kPa CO2; 0.6 kPa O2 + 1.5 kPa CO2; and 0.6 kPa O2 + 1.0 kPa CO2) were tested at 0, 0.5 and 1.0°C, in a 5x3 factorial arrangement. Fruit quality and ripening analyses were performed after eight-month storage plus seven days of shelf-life at 20°C. Oxygen partial pressures below 0.8 kPa increased the occurrence of internal breakdown and mealiness. The best ULO condition was 1.0 kPa O2 + plus 2.0 kPa CO2 at 1.0°C. The interaction of ULO conditions and storage temperatures shows the need of increasing O2 partial pressure at higher storage temperatures.

Marjojen antosyaanien erottaminen ja väkevöinti

Antosyaanit ovat luonnossa esiintyvien flavonoidien suurin ryhmä. Niitä on tunnistettu yli 600 erilaista, mutta kuitenkin vain kuusi on luonnossa yleisesti esiintyviä. Eniten antosyaaneja on tummissa marjoissa kuten mustikassa, marja-aroniassa sekä variksenmarjassa. Antosyaaneilla on havaittu monia positiivisiaterveysvaikutuksia kuten antioksidatiivisia, antikarsinogeenisia, sekä antimikrobiaalisia vaikutuksia. Tässä työssä tutkittiin marjojen antosyaanien talteenottoa uuttamalla sekä niiden väkevöintiä. Tavoitteena oli saada mahdollisimman korkea antosyaanien saanto ja hyvä säilyvyys. Antosyaanien analysointi tehtiin nestekromatografisesti käyttäen ODS-2 kolonnia sekä nopeampaa spektrofotometristä pH-eromenetelmää. Tulokset laskettiin syanidiini-3-glukosidina. Antosyaanien väkevöintiä tutkittiin käyttäen erityyppisiä polymeerisiä makrohuokoisia adsorptiohartseja. Väkevöintiä kokeiltiin myös erottamalla epäpuhtauksia antosyaaniuutteesta sekä esikäsittelemällä puristejäännös eri olosuhteissa ennen antosyaanien uuttoa. Kuiva antosyaaniuute sisälsi ennen väkevöintiä noin 50 mg/g antosyaaneja ja väkevöinnin jälkeen yli 300 mg/g. Antosyaanien säilyvyyttä tutkittiin eri lämpötiloissa sekä kuivana että uutteena. Riippumatta säilytysolosuhteista kuivan puhdistetun antosyaanin havaittiin säilyvän hyvin.

Effect of growth regulators on 'Brookfield' apple gas diffusion and metabolism under controlled atmosphere storage

The objective of this work was to evaluate the effect of growth regulators on gas diffusion and on metabolism of 'Brookfield' apple, and to determine their correlation with quality characteristics of fruit stored in controlled atmosphere. A completely randomized design was used with four replicates. After eight months of storage, the effects of water (control), aminoethoxyvinylglycine (AVG), AVG + ethephon, AVG + naphthaleneacetic acid (NAA), ethephon + NAA, sole NAA, 1-MCP, ethylene absorption by potassium permanganate (ABS), AVG + ABS, and of AVG + 1-MCP - applied at different rates and periods - were evaluated on: gas diffusion rate, ethylene production, respiratory rate, internal ethylene concentration, internal CO2 content, mealiness, and intercellular space. Fruit from the control and sole NAA treatments had the highest mealiness occurrence. Growth regulators significantly changed the gaseous diffusion through the pulp of 'Brookfield' apple, mainly in the treatment AVG + ABS, which kept the highest gas diffusion rate. NAA spraying in the field, with or without another growth regulator, increased ripening metabolism by rising ethylene production and respiration rate, and reduced gas diffusion during shelf life. AVG spraying cannot avoid the ethephon effect during the ripening process, and reduces both the internal space and mealiness incidence, but it is not able to induce ethylene production or to increase respiration rates.

Procedures for evaluating the tolerance of cassava genotypes to postharvest physiological deterioration

Abstract: The objective of this work was to define procedures to assess the tolerance of cassava genotypes to postharvest physiological deterioration (PPD) and to microbial deterioration (MD). Roots of six cassava genotypes were evaluated in two experiments, during storage under different environmental conditions: high temperature and low soil moisture; or low temperature and high soil moisture. Roots were treated or not with fungicide (carbendazim) before storage. Genotype reactions to MD and PPD were evaluated at 0, 2, 5, 10, 15, 20, and 30 days after harvest (DAH), in the proximal, medial, and distal parts of the roots. A diagrammatic scale was proposed to evaluate nonperipheral symptoms of PPD. Fungicide treatment and root position did not influence PPD expression; however, all factors had significant effect on MD severity. Genotypes differed as to their tolerance to PPD and MD. Both deterioration types were more pronounced during periods of higher humidity and lower temperatures. The fungicide treatment increased root shelf life by reducing MD severity up to 10 DAH. Whole roots showed low MD severity and high PPD expression up to 10 DAH, which enabled the assessment of PPD without significant interference of MD symptoms during this period.

Development of a diagrammatic scale for the evaluation of postharvest physiological deterioration in cassava roots

Abstract:The objective of this work was to develop a scale to assess the severity of postharvest physiological deterioration (PPD) of cassava roots, and to validate this scale for accuracy and reproducibility estimates. A diagrammatic scale (0 to 100%) for the damaged roots was analyzed according to precision, accuracy, and reproducibility. Seven evaluators (four with experience and three without it) quantified the PPD severity, with or without the scale, considering 150 roots with different levels of PPD. Without and with the use of the scale, respectively, the inexperienced evaluators obtained coefficients of determination (R2) from 0.76 to 0.86 and 0.87 to 0.92, and the experienced evaluators obtained R2 from 0.90 to 0.96 and 0.96 to 0.97. The values of the intercept (a) obtained by both the experienced and inexperienced evaluators who did not use the scale were all significant, while after using the scale, only two evaluators got values that were not significantly different from one. Evaluation reproducibility between the evaluators ranged from 0.61 to 0.91 for the inexperienced ones and from 0.83 to 0.95 for the experienced ones. The proposed diagrammatic scale was considered appropriate to estimate the severity of PPD in cassava roots, and can be used to identify sources of tolerance to postharvest deterioration.

Water vapor tightness of packages: methods and optimizing

Työn tarkoituksena oli testata jo tutkimuskeskuksella käytössä ollutta ja tutkimuskeskukselle tässä työssä kehitettyä pakkauksen vesihöyrytiiveyteen liittyvää mittausmenetelmää. Saatuja tuloksia verrattiin keskenään sekä materiaalista mitattuihin arvoihin. Elintarvikepakkauksia tutkittiin myös kosteussensoreiden, säilyvyyskokeen sekä kuljetussimuloinnin avulla. Optimoinnilla tutkittiin pakkauksen muodon vaikutusta vesihöyrytiiveyteen. Pakkauksen vesihöyrynläpäisyn mittaamiseen kehitetty menetelmä toimi hyvin ja sen toistettavuus oli hyvä. Verrattaessa sitä jo olemassa olleeseen menetelmään tulokseksi saatiin, että uusi menetelmä oli nopeampi ja vaati vähemmän työaikaa, mutta molemmat menetelmät antoivat hyviä arvoja rinnakkaisille näytteille. Kosteussensoreilla voitiin tutkia tyhjän pakkauksen sisällä olevan kosteuden muutoksia säilytyksen aikana. Säilyvyystesti tehtiin muroilla ja parhaan vesihöyrysuojan antoivat pakkaukset joissa oli alumiinilaminaatti- tai metalloitu OPP kerros. Kuljetustestauksen ensimmäisessä testissä pakkauksiin pakattiin muroja ja toisessa testissä nuudeleita. Kuljetussimuloinnilla ei ollutvaikutusta pakkausten sisäpintojen eheyteen eikä siten pakkausten vesihöyrytiiveyteen. Optimoinnilla vertailtiin eri muotoisten pakkausten tilavuus/pinta-ala suhdetta ja vesihöyrytiiveyden riippuvuutta pinta-alasta. Optimaalisimmaksi pakkaukseksi saatiin pallo, jonka pinta-ala oli pienin ja materiaalin sallima vesihöyrynläpäisy suurin ja vesihöyrybarrierin määrä pienin.

Effects of packaging and temperature on postharvest of atemoya

Effects of refrigerated storage and different packages on postharvest behaviour of fruits of atemoya (Annona cherimola x A. squamosa) cv. PR3 were investigated. Fruits were individually sealed in copolymer (PD-955) and low-density polyethylene (LDPE) bags and stored for 21 days at 15°C or 25°C. Then they were unwrapped and maintained at 25°C, for ripening. Weight loss and firmness of fruits were both affected by storage time, temperature and packaging. Weight loss in packaged atemoyas was lower than in the control, non-wrapped fruits. A non-trained panel scored the atemoyas for overall eating quality and appearance. Fruits sealed in LDPE did not ripen, probably due to an injurious atmosphere developed inside the package. Atemoyas packaged in PD-955 film had a shelf-life of 17 days against 13 days of the control ones, both stored at 15°C, an increase of 30% on shelf-life.

Effects of biofilm and refrigeration on acerola postharvest conservation

The objective of this work was to compare the effects of four different concentrations of cassava starch film and storage temperature on shelf life and the quality of a genotype of acerola from the Germplasm Active Bank (GAB) of Federal Rural University of Pernambuco, Brazil. Sound orange-reddish acerola fruits were washed with a chlorine solution (100 mg.L-1 active chlorine) and randomly distributed into different lots. The fruits were dipped for 3 min in a cassava starch suspension with concentrations of 1, 2, 3 and 4% (w/v) and the control without coating, stored at 10ºC (85% RH) and 22ºC (85% RH). The total soluble solids (TSS), pH, titratable acidity (TA) and ascorbic acid (AA) were determined at harvest and regular interval during storage. The use of cassava biofilm at 1% on acerola fruits maintained the highest ascorbic acid content and the temperature of 10ºC extended storage life. The fruits coated with 1 and 2% biofilm could be stored for a period up to 15 days at 10ºC, with acceptable quality characteristics.