Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice

The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic films after dark storage at 20°C. Owing to absorption, the amount of flavour compounds in the model solution exposed to LDPE decreased substantially. From the model flavour solution valencene was almost completely absorbed by LDPE, followed to a lesser extent by decanal, hexyl acetate, octanal and nonanone. Less flavour compounds were absorbed from the model solution by PC and PET. In contrast to LDPE, valencene was absorbed in the lowest amounts and decanal in the highest. Limonene was readily absorbed from orange juice by LDPE, while myrcene, valencene, pinene and decanal were absorbed in smaller quantities. Only three flavour compounds were absorbed from orange juice by PC and PET in very small amounts: limonene, myrcene and decanal. Although the flavour content between controls and polymer-treated samples differed substantially, the loss of flavour compounds due to absorption by LDPE, PC and PET did not influence taste perception of a model solution and orange juice significantly up to 29 days of dark storage at 20°C as determined by triangular taste panel tests.     

Influence of solvent absorption on the migration of Irganox 1076 from LDPE

The effect of solvent absorption on additive migration was studied by relating the diffusion coefficient ( D ) of Irganox 1076 to the maximum solvent absorption of different solvents in low-density polyethylene (LDPE) film. Solvents tested were ethanol, isopropanol, isooctane, ethylacetate, cyclohexane, tributyrin, tricaprylin and olive oil. Diffusion and partition coefficients were determined by fitting the migration curves, i.e. the concentration of Irganox 1076 in solvent as a function of time, with Fick's diffusion equation. The results for the low molecular weight solvents show that with increasing maximum solvent absorption, D of Irganox 1076 is increasing as well. This trend is not observed for the two triglycerides and olive oil. In spite of absorption, no increase in D was observed. The obtained result is the basis of an extended predictive migration model that, besides migrant and polymer properties, is also based on the maximum solvent absorption in the polymer.     

Quality and safety aspects of reusable plastic food packaging materials: A European study to underpin future legislation

The objective of this study was to develop a comprehensive package of quality assurance criteria for use by industry and regulatory authorities for ensuring the quality and safety-in-use (sensory, microbiological and chemical) of reused plastics for food packaging. The study included thermal degradation effects, flavour carry-over caused by flavour and off-flavour substances, the influence of washing processes on the materials, and the efficiency of washing processes in removing offflavour substances and surrogate substances representing misuse chemicals as might be put in bottles by consumers. The microbial safety of the refillable plastic articles in relation to commercial washing processes and the industrial procedures applied has also been investigated. Lastly, the suitability of laboratory procedures using strips of bottle material for predicting the sorption and washing properties of refillable plastic bottles has been studied. In general it is concluded that reuse of the articles does not significantly influence any of the properties investigated. Neither the chemical, physical nor surface properties seem to be significantly influenced by repeated washing. It can be concluded, however, that it is very likely that most of the articles investigated will cause flavour carry-over to a new filling if they are contaminated with strongly flavoured products. Finally it can be concluded that the procedures evaluated can serve as a basis for future legislation on refillable articles, but for several procedures (like quick predictive testing with strips) more investigation is required to create a more solid basis.     

Effect of ionizing radiation on the physicochemical and mechanical properties of commercial monolayer flexible plastics packaging materials

The effect of γ-radiation doses (5, 10, 30 kGy) on the mechanical properties, gas and water vapour permeability, infrared (IR) spectra, and overall migration into aqueous and alternative fatty food simulants of commercial monolayer flexible packaging films ethylene vinyl acetate (EVA), high-density polyethylene (HDPE), polystyrene (PS), bi-axially oriented polypropylene (BOPP), low-density polyethylene (LDPE) and Ionomer was studied. For comparison purposes, respective non-irradiated (control) films were also studied. The results showed that radiation doses of 5, 10 and 30 kGy did not induce any statistically significant changes in the permeability of all studied films to gases (oxygen and carbon dioxide) and water vapour. Likewise, IR spectra of all studied films showed no significant differences after all absorbed doses. The mechanical properties (tensile strength, percentage elongation at break and Young's modulus) of all studied films remained unaffected after absorbed doses of 5 and 10 kGy. In contrast, the tensile strength of HDPE, BOPP and Ionomer films irradiated at a dose of 30kGy decreased. In addition, the percentage elongation at break of LDPE and Ionomer films irradiated at a dose of 30 kGy decreased while Young's modulus of all samples remained unaffected. All mechanical properties of PS and EVA films remained unaffected after radiation at 30 kGy. Radiation (all absorbed doses) resulted in no statistically significant differences in overall migration values into distilled water for all studied films. For 3% aqueous acetic acid, absorbed doses of 5 and 10 kGy did not affect overall migration values of all investigated samples with the exception of the Ionomer film, for which the overall migration value decreased at 10 kGy. An absorbed dose of 30 kGy caused an increase in BOPP overall migration values and a decrease in Ionomer overall migration values. In contrast, a dose of 30 kGy induced no changes in overall migration values of EVA, HDPE, LDPE and PS films into the same simulant. There were no statistically significant differences in overall migration values of EVA, PS and LDPE films into iso-octane for all absorbed doses. In contrast, a dose of 30 kGy resulted in an increase in overall migration values of BOPP and a respective decrease in HDPE and Ionomer films.     

Influence of flavour enhancement on food liking and consumption in older adults with poor,moderate or high cognitive status

It is important to maintain adequate food consumption in older adults so as to prevent malnutrition, particularly among those with cognitive impairments who represent the majority of patients living in nursing homes. Indeed, these patients may reduce their food intake, which can be explained by a lack of pleasure in eating food. Few studies have tested the efficiency of strategies based on food pleasure to increase food intake in this population. To our knowledge, the influence of flavour enhancement has been widely investigated in non-cognitively impaired older adults, but not in those with cognitive impairments. Our objective was therefore to study the influence of flavour enhancement on food liking and then on food intake in older adults with different degrees of cognitive impairments. To achieve this, two food testing methods were compared: paired comparison and sequential monadic tests.104 subjects were recruited in four nursing homes and clustered into three groups as a function of their cognitive impairments (severe, moderate and without marked cognitive impairments). Two different samples of an appetizer were formulated: a reference sample and a flavour-enhanced sample. These appetizers were offered to the participants before lunch in standardised small portions during three tasting sessions organised at intervals of one week. During one session, the participants received both samples at the same time (paired comparison test) and during the two others, they were given a single sample at each session (sequential monadic test). Food intake and food liking were then evaluated with respect to each participant and each sample.The results showed a positive correlation between food liking and food intake, and a positive influence of flavour enhancement on food intake, regardless of the cognitive status of the participants. The sequential monadic test produced results similar to those of the paired-comparison test in terms of the effects of flavour enhancement. These findings suggest that this method could be used to investigate the influence of food interventions at mealtimes in older adults with cognitive impairments.Finally, this study shows that food intake could be increased by optimising the sensory properties of foods served to cognitively impaired older patients.     

Enhancing expected food intake behaviour,hedonics and sensory characteristics of oil-in-water emulsion systems through microstructural properties,oil droplet size and flavour

Food reformulation, either to reduce nutrient content or to enhance satiety, can negatively impact upon sensory characteristics and hedonic appeal, whilst altering satiety expectations. Within numerous food systems, perception of certain sensory attributes, known as satiety-relevant sensory cues, have been shown to play a role in food intake behaviour. Emulsions are a common food structure; their very nature encourages reformulation through structural design approaches. Manipulation of emulsion design has been shown to change perceptions of certain sensory attributes and hedonic appeal, but the role of emulsions in food intake behaviour is less clear. With previous research yet to identify emulsion designs which promote attributes that act as satiety-relevant sensory cues within emulsion based foods, this paper investigates the effect of oil droplet size (d_4,3: 0.2–50 μm) and flavour type (Vanilla, Cream and No flavour) on sensory perception, hedonics and expected food intake behaviour. By identifying these attributes, this approach will allow the use of emulsion design approaches to promote the sensory characteristics that act as satiety-relevant sensory cues and/or are related to hedonic appeal. Male participants (n = 24) assessed the emulsions. Oil droplet size resulted in significant differences (P < 0.05) in ratings of Vanilla and Cream flavour intensity, Thickness, Smoothness, Creamy Mouthfeel, Creaminess, Liking, Expected Filling and Expected Hunger in 1 h’s time. Flavour type resulted in significant differences (P < 0.05) in ratings of Vanilla and Cream flavour intensity, Sweetness and Liking. The most substantial finding was that by decreasing oil droplet size, Creaminess perception significantly increased. This significantly increases hedonic appeal, in addition to increasing ratings of Expected Filling and decreased Expected Hunger in 1 h’s time, independently of energy content. If this finding is related to actual eating behaviour, a key target attribute will have been identified which can be manipulated through an emulsions droplet size, allowing the design of hedonically appropriate satiating foods.     

Influence of heat treatment on carnosine, anserine and free amino acid composition of beef broth and its role in flavour development

 In an attempt to determine the most important free amino acids (FAAs) in the development of the flavour of beef broths, the amino acid compositions of beef broths prepared at different temperatures and cooking times, with flavours of different intensities, were studied. From our data, broths obtained at temperatures above 75  °C and cooking times longer than 120 min had significantly lower levels of most of the FAAs studied (P<0.05). Statistical analysis of the sensorial and analytical data (principal component analysis, chi-square analysis) permitted the different FAAs to be grouped in relation to the flavour. There was a significant association between elevated levels of glutamic acid, asparagine (P<0.01), lysine and methionine (P<0.05) and the development of beef broth flavour. However, this was inversely related to levels of cysteine, proline, serine, M-histadine, tyrosine, valine, arginine and aspartic acid whereas reduced levels of β-alanine, asparagine, tyrosine, threonine, methionine, cysteine, leucine, isoleucine, tryptophan, glutamic acid, histidine, lysine and phenylalanine were associated with sapid properties not characteristic of beef broths (astringent, warmed-over flavours). A significant correlation (P<0.01) between sensory evaluation and carnosine and anserine levels was also observed. Received: 29 December 1998 / Revised version: 29 April 1999     

Influence of food matrix on absorption of flavour compounds by linear low‐density polyethylene: proteins and carbohydrates

The effects of differences in food matrices on the absorption of four flavour compounds (limonene, decanal, linalool and ethyl 2‐methyl butyrate) into linear low‐density polyethylene (LLDPE) were studied using a large volume injection GC ‘in vial’ extraction method. Food components investigated included β‐lactoglobulin (β‐lg), casein, pectin, carboxymethylcellulose (CMC), lactose and saccharose. β‐lg interacted irreversibly with decanal (P < 0.01) and suppressed absorption of the latter by LLDPE by more than 50% after 14 days of exposure. Casein was capable of binding limonene and decanal (p < 0.05) by hydrophobic and covalent interactions, resulting in decreased absorption of 40% and 90%, respectively. The absorption rates of limonene, and to a leaser extent decanal, were decreased in presence of pectin and CMC. Increasing viscosity slowed down diffusion of flavour compounds from the matrix to LLDPE. An increase of absorption (p < 0.01) was observed for linalool and ethyl 2‐methyl butyrate, due to a ‘salting out’ effect caused by lactose and saccharose. The absorption of decanal was decreased (p < 0.01) after 14 days of exposure in the presence of lactose, saccharose and CMC. There might be an interactive effect between a sugar (residue) and decanal. Knowledge of the composition of a food matrix and packaging material is necessary to estimate the amount of flavour absorption. © 2000 Society of Chemical Industry     

Influence of chewing gum packaging design on consumer expectation and willingness to buy. An analysis of functional, sensory and experience attributes

This paper studies the influence of two design variables of chewing gum packaging, those of colour and format, on consumer expectations of specific product attributes and willingness to buy. Some 390 consumers participated in this investigation, evaluating a total of 30 functional, sensory and experience attributes for nine different packaging designs. The results demonstrate that packaging format influences expectations of functional attributes, sensory attributes of texture and experience attributes, while colour influences expectations of sensory attributes of taste and flavour and experience attributes. The study also reveals that willingness to buy is more closely related to the colour of the packaging than to its format.     

Effect of oxygen absorber, nitrogen flushing, packaging material oxygen transmission rate and storage conditions on quality retention of raw whole unpeeled almond kernels (Prunus dulcis)

The present study investigated the effect of active packaging, nitrogen flushing, container oxygen barrier and storage conditions on quality retention of raw whole unpeeled almonds. Almond kernels were packaged in: a) polyethylene terephthalate//low-density polyethylene (PET//LDPE), and b) low-density polyethylene/ethylene vinyl alcohol/low-density polyethylene (LDPE/EVOH/LDPE) pouches under N_2, with or without an oxygen absorber, heat-sealed and stored for a period of 12 months. Quality parameters monitored were: peroxide value (PV), hexanal content, color, fatty acid composition and volatile compounds. PV ranged between 0.17 for fresh almonds and 9.22 meq O₂/kg oil for almonds packaged in PET//LDPE pouches under N₂ exposed to light at 20 °C after 12 months of storage. Respective values for hexanal were <28.5 μg/kg and 4.88 mg/kg. Polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFA) increased with a parallel decrease of monounsaturated fatty acids (MFA) after 12 months of storage in all treatments. Likewise, volatile compounds such as aldehydes, ketones, alcohols, alkanes and aromatic hydrocarbons increased indicating enhanced lipid oxidation. Color was the parameter least affected. Use of the oxygen absorber provided a shelf life of at least 12 months for all samples irrespective of container oxygen barrier, lighting conditions and storage temperature.