Search results for "plastic film"

Enhancement of immunohistochemical staining

1982

The present paper describes two simple procedures which enhance immunohistochemical staining. One is to cover the sections with a plastic film to keep the serum uniformly distributed and minimize its evaporation. Secondly, rocking of the slides has been introduced, causing the serum to flow back and forth under the plastic film. Using this system, it has been possible to test for the effect of mixing on an immunohistochemical reaction (the demonstration of calcitonin in thyroid C cells). It has been found that mixing definitely enhances the reaction during the first 8 h. No effect of serum volume was observed.

Improvement of plum storage with modified atmosphere packaging

2010

Post-harvest supply chain is a critical point for agro-food marketing. The management of freshness in the storage is fundamental to maintain high profits in the agro-food sector to improve the distribution and to respond to retailers and consumers' requirements. Plums are considered to have a climacteric-ripening pattern, in which ethylene is the hormone responsible for ripening. Modified atmosphere (MA) storage is a method helpful to maintain the natural quality of fruits. MA added to low temperatures influence fruit metabolism and reduce ethylene production, weight losses, hardness of pulp, preserving vitamins and organic acids. The objective of this study was to increase the condition of…

RESPONSE OF MELON GENOTYPES TO POLYETHYLENE AND BIODEGRADABLE STARCH-BASED MULCHING FILMS USED FOR FRUIT PRODUCTION IN THE WESTERN COAST OF SICILY

2009

Solar UV-B radiation affects leaf quality and insect herbivory in the southern beech tree Nothofagus antarctica

2004

We examined the effects of solar ultraviolet-B (UV-B) radiation on plant-insect interactions in Tierra del Fuego (55°S), Argentina, an area strongly affected by ozone depletion because of its proximity to Antarctica. Solar UV-B under Nothofagus antarctica branches was manipulated using a polyester plastic film to attenuate UV-B (uvb-) and an Aclar film to provide near-ambient UV-B (uvb+). The plastic films were placed on both north-facing (i.e., high solar radiation in the Southern Hemisphere) and south-facing branches. Insects consumed 40% less leaf area from north- than from south-facing branches, and at least 30% less area from uvb+ branches than from uvb-branches. The reduced herbivory …

EFFECTS OF PLASTIC MULCH AND FLOATING COVER ON LETTUCE PRODUCTION IN SICILY

2012

The use of floating cover directly applied on top of the crop is rapidly increasing on leafy vegetables like lettuce as a simple, inexpensive and effective technique to induce earliness. Two lettuce types, ‘Iceberg’ and ‘Romaine’, under two different crop management systems (black plastic mulch and black plastic mulch combined with floating cover) were tested in Sicily in 2007. Plug type transplants were planted at the end of January on double rows. The nonwoven floating cover was applied after transplanting. Maximum and minimum air temperatures below the floating cover during the growing period were in the average 5 and 1.5°C higher than those without cover. Lettuces mulched and protected …

Influence of greenhouse different coverings on chemical and physical risk factors

2005

Crop production in greenhouses needs the use of chemicals and requires high levels of temperature and relative humidity to assure the increasing of crop production. This can cause risks for the health of the operators, especially if they are not equipped with protection devices. The risks may also vary with the type and/or size and/or shape of the protected structures. In order to determine the influence of different coverings on type and amount of risks, chemical and physical risk factors were measured inside greenhouses with different cladding materials (glass panels and plastic films) after crop management. In these two different greenhouses typologies, that were similar for location and…

Structure and thermal properties of a chitosan coated polyethylene bilayer film

2012

The thermal and the structural properties of chitosan coated polyethylene (PE) films were studied. The coating process did not significantly influence the thermal stability and the PE surface structure and/or composition of the polyolefin. Dehydration temperature of chitosan films reflected the strength of water/acetic acid/chitosan chains interactions. Glycerol, used as a plasticizer, formed new hydrophilic centres in the film matrix. Moreover it was better integrated in the CSEGLY than in CSAGLY network. Besides, the addition of a plasticizer in the chitosan films decreased the film degradation temperature. There were two main steps for the PE chitosan coated films degradation. The first …

Water barrier properties of treated-papers and application to sponge cake storage

2006

Abstract Water barrier properties of three treated papers and of one plastic film were compared and the potential of these packaging films to prevent moisture loss from a sponge cake during storage in standard conditions (25 °C and 50% relative humidity gradient) was evaluated. Sorption isotherms were established at 25 °C for both sponge cake and papers, from which diffusivity values in papers were determined for the whole range of A w . Permeability of packaging films was determined in standard conditions. Water sorption was close for all papers, regardless of their treatment, whereas water diffusivity was reduced by coating or calendering. Water vapor permeability in papers was controlled…

A new approach to studying sponge cake aroma after storage in treated paper and plastic packaging by direct gas chromatography–olfactometry (D-GC–O)

2007

The objective of this study was to use D-GC–O to compare the global odour of a sponge cake flavoured with either a ‘viennoiserie’ aromatic note or a simplified mixture of aroma compounds (used for physicochemical studies), then stored in a glass packaging (inert and impermeable) or in pouches made with treated papers or with plastic packaging, in accelerated ageing conditions (high temperature and relative humidity gradient). After 1 week of storage, the flavoured sponge cake headspace was SPME-extracted directly into the packaging and analysed by D-GC–O. The sponge cake global odour was better retained if plastic film rather than treated-papers was used, for both flavourings. Changes in th…

Tracer aroma compound transfer from a solid and complex-flavored food matrix packed in treated papers or plastic packaging film.

2007

The objective of this work was to study the transfer of four aroma compounds (ethyl butyrate, ethyl hexanoate, cis-3-hexenol, and benzaldehyde) from a solid and complex-flavored food matrix (sponge cake) toward and through packaging films placed in indirect contact during storage in accelerated aging conditions (38 °C and 86% relative humidity gradient). The efficiency of treated papers relative to that of standard paper and plastic as barrier was tested. Before storage, aroma compound volatility in the sponge cake was measured, and similar values were found between aroma compounds, due to the fat content of the sponge cake. Whatever the aroma compound, permeability values during storage we…