Effect of packaging and storage conditions on development of warmed-over flavour in sliced, cooked meat

Summary The development of warmed-over flavour (WOF) in a pilot-scale experiment was followed by sensory evaluation and three objective methods (thiobarbituric acid reactive substances, relative hexanal content, and fluorescent lipid oxidation products) during 14 days of chill storage at 4° C of sliced, cooked lean beef using three different packaging conditions: (1) in air in a polyethylene foil (PE); (2) in 99% vacuum in a laminate foil with low oxygen transmission rate (VAC); (3) in a modified atmosphere (30% CO₂/70% N₂) in a laminate foil with low oxygen transmission rate (MAP). Each of the objective methods correlated well with the sensory evaluation. The sensory quality of the meat packed in PE was clearly inferior to the VAC and MAP packed meat, having less meat taste and a perceptible degree of WOF when reheated after only 1 day of storage, increasing to an unacceptable level within 3 days of storage. In contrast, the sensory quality of the VAC and MAP packed meat remained high throughout the storage period. Irrespective of packaging method, no effect of light during the chill storage period on the development of WOF was detected. MAP packaging for precooked beef was tested on a larger scale in a senior citizen food service system. The results showed that in a practical application of MAP the major problem in avoiding WOF was the achievement of a sufficiently low residual oxygen content in the packages.

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Einfluß der Verpackung und Lagerungsverhältnisse auf die Entwicklung des Aufwärmgeschmacks von in Scheiben gekochtem Rindfleisch

Zusammenfassung In einem Modellversuch mit in Scheiben geschnittenem gekochtem Rindfleisch wurde die Entwicklung des Aufwärmgeschmacks mit sensorischer Beurteilung und drei objektiven Methoden (Thiobarbitursäure-reaktive Substanzen, relativer Gehalt von Hexanal und fluorescierenden Fettoxidationsprodukten) während 14tägiger Kühllagerung bei 4 °C untersucht. Das Fleisch wurde auf drei verschiedene Weisen verpackt: (1) mit Luft in Polyäthylenfolie (PE); (2) in 99% Vakuum in laminierter Folie mit niedriger Sauerstoffdurchlässigkeit (VAC); (3) in modifizierter Atmosphäre (30% CO₂/70% N₂) in laminierter Folie mit niedriger Sauerstoffdurchlässigkeit (MAP). Jede objektive Methode korrelierte gut mit der sensorischen Beurteilung. Die sensorische Qualität des PE-Fleisches war merkbar geringer als die des in VAC und MAP verpackten Fleisches. Es hatte nach nur einem Tag Kühllagerung einen geringen Fleischgeschmack und einen merklichen Aufwärmgeschmack, der nach drei Tagen auf ein unakzeptables Niveau zugenommen hatte. Demgegenüber war die sensorische Qualität des in VAC und MAP verpackten Fleischs sehr gut über die ganze Lagerungszeit. Beleuchtung hatte, ungeachtet der Verpackungsmethode, auf die Entwicklung des Aufwärmgeschmacks keinen Einfluß. Bei modifizierter Atmosphärenverpackung von gekochtem Fleisch in größerem Ausmaß in einer Küche zur Verköstigung von älteren Menschen ergab es sich, daß das größte Problem, den Aufwärmgeschmack zu vermeiden, ein ausreichend kleiner Restsauerstoffgehalt in den Verpackungen war.

     

The influence of storage conditions on flavour changes in human milk

The effects of freeze-storage on human milk have been investigated with regard to sensory changes and modifications in the molecular composition of constituent odour-active volatiles. Sensory evaluation showed that fishy-metallic odour attributes are generated during storage, as are rancid-sweaty odour notes, which were described by panellists to be highly unpleasant. To monitor the dynamics of off-odour development in human milk, sensory evaluation in both orthonasal and retronasal mode was performed at defined time intervals of storage, with parallel evaluation of human milk samples that had been heated prior to freeze-storage. Heating was found to induce slight flavour changes, with generation of a predominantly egg-white-like note, but with no further generation of off-odour formation upon subsequent storage. This suggests that the formation of the off-odour in non-heated milk resulted from metabolic processes in the milk, although may also be due to the specific composition of human milk. In comparison, similar off-odour development was not observed in bovine milk. Molecular identification of the off-odour substances, most specifically free fatty acids and oxidation derivatives of polyunsaturated fatty acids, indicated both lipolytic and peroxidative processes of components of the native human milk. Finally, these results indicate that human milk is obviously a highly sensitive food material, specifically with regard to its characteristic fatty acid composition.     

Influence of transport and storage conditions on beer quality and flavour stability

Breweries are exporting their brands overseas, resulting in an increasingly competitive and globalised beer market. Inevitably, the beer experiences varying and prolonged periods of transport and storage prior to consumption. During this process, the flavour of fresh beer deteriorates, leading to the presence of stale flavours and a decrease in the drinkability of the beer. Results reported here show that an increased temperature during beer transport and storage causes significant flavour deterioration, as determined analytically (increase in aldehydes, beer colour and haze formation, decrease in iso‐α‐acids concentration) and sensorially (increase in overall aging score). Further, laboratory experiments show that the vibration of beer results in a rapid decrease of oxygen. Moreover, inappropriate storage temperature has a negative effect on beer quality and stability, in particular when combined with vibration. © 2018 The Institute of Brewing & Distilling     

Changes in volatile flavour compounds in field pea cultivars as affected by storage conditions

The impact of storage conditions on volatile flavour profile of field pea cultivars was evaluated. Seeds were kept at 4 °C, room temperature (approximately 22 °C) and 37 °C for 12 months. Headspace solid‐phase microextraction gas chromatography–mass spectrometry was used for extraction and identification of volatile flavour compounds (VFCs). Significant (P < 0.01) differences in the concentration of VFCs were observed during storage. All cultivars kept at 22 and 37 °C had higher mean value of aldehydes compared to those kept at 4 °C. Alcohols, hydrocarbons, ketones, terpenes and esters were higher in samples stored at 4 °C compared to those at higher temperatures. 1‐Hexanol, hexanal, styrene, 2‐butanone, dimethyl sulphide, 3‐carene, ethyl acetate and 2, 3‐diethyl‐5‐methyl pyrazine were the most abundant compounds found in peas. Results from this study could be useful in identifying improved conditions of storage to enhance flavour properties of peas.     

Modification of in-pack conditions to extend the storage life of vacuum packaged lamb

High pH (>5·9) lamb loins from a research abattoir were subjected to differing packaging treatments to determine whether package modification could reliably extend the storage life of chilled lamb cuts beyond that attained by cuts vacuum-packaged in film of low gas permeability, as in current commercial practice. Treatments applied were carbon dioxide flushing or addition of a citrate buffer (pH 4·8), a 5% lactic acid solution or a Lactobacillus inoculum (plastic packs only) and packaging in a plastic film of moderately low oxygen permeability (140 cc/m(2)/24 h at 25°C and 90% relative humidity) or in a foil laminate of immeasurably low oxygen permeability. After 12 weeks' storage at -0.5°C, the cuts packaged in the plastic film were spoiled by off-odours produced by enterobacteria, except for inoculated cuts, which, instead, had developed unacceptable dairy flavours. In contrast, cuts packaged in foil laminate developed floras of lactobacilli that had not caused spoilage after 12 weeks, and meat colour was much improved by the exclusion of oxygen. Loin cuts from a commercial packaging operation were packaged in a shrinkable plastic film of low oxygen permeability (30 to 40 cc/m(2)/24 h at 25°C and 90% relative humidity), in foil laminate, or in foil laminate after the addition of 5% lactic acid solution. For the first 6 weeks, cuts were stored in a commercial chiller nominally operating at 0°C; subsequently, they were held in a laboratory chiller at -0.5°C. Some cuts packaged in the shrinkable plastic were spoiled after 9 weeks' storage and all were spoiled at 12 weeks, because of off-flavours produced by enterobacteria. All cuts packaged in the foil laminate were very acceptable at 9 weeks but most were spoiled by off-flavours at 12 weeks. Most cuts treated with lactic acid and packaged in foil laminate were unspoiled after 12 weeks. The packaging requirements indicated to be necessary for reliable extension of the storage life of vacuum packaged lamb are discussed.     

干酪脂类的代谢及其对风味的作用

干酪成熟期间脂类的代谢对干酪风味有着重要的作用。文中对干酪中的脂类、脂肪酸、干酪的脂解作用和参与其中的酶,以及干酪成熟过程中脂解作用对干酪风味的作用进行了探讨,并对存在的问题和今后的研究方向进行了分析。     

Retail colour display life of chilled lamb as affected by processing conditions and storage temperature

This study explored the impact of i) processing conditions (electrical stimulation and pre rigor temperatures), and ii) storage temperature prior to retail display on the colour stability of lamb which had been vacuum-packaged for seven weeks before retail packaging in high-oxygen modified atmosphere (80% O(2)/20% CO(2)). A high pre rigor temperature (42°C) reduced colour stability while differences in colour stability between pre rigor temperatures of 5°C, 15°C and 25°C were limited. It was not affected by electrical stimulation, and did not interact with pre rigor temperature. In contrast, an increase in the storage temperature from the ideal temperature of -1.5°C to 2°C significantly decreased the colour stability of lamb loins. Even one week at 2°C at the end of the storage period had a substantial negative impact on the retail colour display life. The variability in colour increased over time, and the variability increased more for the temperature abuse treatments.     

A model explaining and predicting lamb flavour from the aroma-active chemical compounds released upon grilling light lamb loins

The objective of the work is to understand the role of the different aroma compounds in the perception of the local “lamb flavour” concept. For this, a set of 70 loins (Longissimus dorsi) from approximately seventy day-old Rasa Aragonesa male lambs were grilled and the aroma-active chemicals released during the grilling process were trapped and analyzed. Carbonyl compounds were derivatizated and determined by GC-NCI-MS, whereas other aromatic compounds were directly analyzed by GC-GC-MS. Odour activity values (OAVs) were calculated using their odour threshold values in air. Lamb flavour could be satisfactory explained by a partial least-squares model (74% explained variance in cross-validation) built by the OAVs of 32 aroma-active chemical compounds. The model demonstrates that the lamb flavour concept is the result of a complex balance. Its intensity critically and positively depends to the levels of volatile fatty acids and several dimethylpyrazines while is negatively influenced by the different alkenals and alkadienals. (E,E)-2,4-decadienal and (E)-2-nonenal showed top OAVs.     

Beef broth flavour: study of flavour development

Of the range of preparation conditions studied here, the beef broths with the most favourable sensory characteristics (P ≤ 0.05) were those manufactured with minced meat in a 7.5 g l⁻¹ NaCl solution in proportions of 1:2 (w/v), heated at 85 °C for 60 min (the beef broth flavour was clean, clear, without any off‐flavour). Our data indicate the importance of accurately determining the heat treatment, since intermediate treatments yielded beef broths of good quality, whereas less intense treatments produced broths with raw meat and bloody and metallic flavours, and intensely heated broths had a warmed‐over or sour and astringent flavour. At higher temperatures the cooking time required to obtain a good‐quality broth decreased. From the analysis of variance of the sensorial data, temperature plays a more important role than cooking time in the development of the sensory properties of beef broths. © 2000 Society of Chemical Industry     

The effect of some manufacturing conditions on the development of flavour in Cheddar cheese

Organoleptic assessments by the NIRD panel of Cheddar cheeses made with Streptococcus cremoris NCDO 924 or 1986, either in enclosed vats excluding nonstarter flora or in open vats, showed that high viable starter populations in curd did not give stronger-flavoured cheese, but led to the development of bitterness. Cheeses made in open vats developed typical flavour more rapidly than those made in enclosed vats. Maturation temperature was the most important factor in determining the flavour intensity; cheese ripened at 13d?C for six months had stronger flavour than corresponding ones ripened at 6d?C for nine months, irrespective of the starter or vat used.     

Application of headspace solid-phase microextraction to volatile flavour profile development during storage and ripening of kiwifruit

Kiwifruit volatile flavour compounds were evaluated with headspace solid-phase microextraction (SPME) as a sample concentration technique. Gas chromatography–mass spectrometry (GC–MS) was used for qualitative and semi-quantitative analysis after SPME. Components such as heptanal, ethyl hex-3-enoate, 6-methylhept-5-en-2-one, acetic acid, c/t-2-nonenal (mixture) and c/t-2-decenal (mixture), which were previously found only in kiwifruit juice, were detected by headspace SPME–GC–MS. Other compounds (pent-4-enal, t,t-nona-2,4-dienal, 2-nonanone, ethyl octanoate, butyrolactone and 2-propenyl butanoate), which had not been found previously, were identified. Flavour volatiles of kiwifruit were very sensitive to storage time and state of ripeness.     

Heat and storage effects on the flavour of peanuts

Two peanut varieties, Giza 4 and Giza 5 were subjected to different heat treatments such as drying in solar drier at air speed 0.5 and 2 m/sec with average temperature 45 and 60°C and heating in oven at 120 and 150°C. The sensory evaluation of the two varieties showed insignificant differences among varieties and heating processes. A correlation between the sensory and instrumental data was found. The high sensory scores of samples heated at 150°C were attributed to the presence of high concentration of pyrazines which were thought to contribute to flavour and aroma of fresh roasted peanut. A comparative study between the main chemical classes retained in peanut samples after storage for 3 months at room temperature showed that the aldehydes derived lipids increased significantly in the solar dried samples. The antioxidative components produced via Maillard reaction resulted in oxidative stability of the samples heated in oven     

Soybean variety and storage effects on soymilk flavour and quality

Soymilk prepared from five soybean cultivars, grown in Ontario, were analysed for protein, oil, mineral composition, viscosity, colour, lipoxygenase (LOX) activities and flavour profile. Among the five soybean cultivars, the Vinton 81 variety contained the highest protein and the lowest fat. The yield of soymilk from all five cultivars was similar. Major differences were observed in viscosity and in the composition of both the soymilk and the okara. Higher protein and fat extractability was found in soymilk made from S08‐80 and Vinton 81 varieties. Their okara protein contents were also among the highest. Minimum extractability was observed with S03W4 cultivar. Soymilk made from S 03W4 and Vinton 81 cultivars had the whitest colour (lowest ΔE values). Viscosity values were the highest for S08‐80, FG1 and S20‐20 varieties. Headspace solid‐phase microextraction gas chromatography was used to analyse volatile compounds in soymilk. A total of fourteen volatiles were identified, among which aldehydes and their corresponding alcohols were the major compounds. Similar volatile compounds were identified in all the samples analysed but at different concentrations. The highest LOX activity was observed in the Vinton 81 and S20‐20 soybean cultivars, which had the highest total volatile and hexanal contents. A positive correlation (correlation coefficient = 0.82) between enzymatic activity and the total volatiles was observed. Vinton 81 cultivar was subjected to storage (at 18 °C and 50% relative humidity) for a period of 10 months. Soymilk was prepared at different times during storage. The results showed that the soymilk colour, LOX and total volatiles were significantly (P < 0.05) affected by the storage of the soybeans over time.     

The microbiology and storage stability of vacuum packed lamb

Lamb joints (shoulders, loins and legs) stored in vacuum packs at 0–1°C remained unspoiled for 6 weeks, but since the aerobic storage life at 5°C (retail shelf life) of lamb after holding in vacuum packs at 0–1°C for 6 weeks was only 2 days, vacuum storage should be limited to a maximum of 4 weeks in practice. Brochothrix thermosphacta , Moraxella spp, and Moraxella-like organisms were predominant on aerobically spoiled lamb and the preservative effect of vacuum packing resulted from the inhibitory effects of the high carbon dioxide (>20%) and low oxygen concentrations (<1%) which developed in the packs. Brochothrix thermosphacta was not completely inhibited, however, and with lactic acid bacteria was the possible cause of cheesy/sour odours which terminated vacuum packed storage life.     

鲜味剂的应用及发展前景

文章介绍了鲜味剂的种类、影响鲜味剂鲜味效果的因素,阐述了鲜味剂在食品工业中的发展前景.     

Influence of pasture species on the flavour, odour and keeping quality of lamb and mutton

Lambs fed white clover species (Trifolium repens cv. Grasslands Huia or cv. Grasslands 4700) showed a stronger flavour in the fat and lean and a greater intensity of odour in the casseroled 12th rib chop than lambs fed on perennial ryegrass (Lolium perenne). The results for hoggets generally supported those for lambs. Differences in flavour of the lean of the lambs appeared within three weeks from the beginning of the experiment. Differences in intensity of flavour and odour between the shoulder, loin and leg of the hoggets were small. After storage for 8 months at —15°, the thiobarbituric acid (TBA) values of the lean and fat of the 12th rib chop were highly significantly greater in lambs fed white clover than in those fed perennial ryegrass. Similar differences were found in hoggets using carcasses that had been stored for one to two months. In the hoggets, significantly higher TBA values were found in the fatty tissues of the leg than in the loin and shoulder. Differences between the TBA values of the lean were not significant.