Studies of incorporation and stability of model flavouring compounds on black tea

Flavoured teas have a good potential and popularity in the export market. In the present studies, four model flavouring compounds, i.e. citronellol, phenylethylalcohol, citral and bergamot oil, were incorporated in black tea and their storage characteristics were studied at three temperature conditions, 5°C, ambient and 37°C, using laminated aluminium foil, metal can and metallised polyester as packaging materials, for a period of 90 days. These were evaluated by instrumental (gas chromatography/ultraviolet) and sensory methods. Considerable flavour loss was observed in metallised polyester package, at 37°C and during the first month of storage. The first three flavoured teas showed a shelf life of 90 days while the bergamot flavoured tea had a shelf life of only 60 days. Highly significant linear correlation was established between the instrumental and sensory values.     

Effect of packaging and storage on the keeping quality of pickled quail eggs

Storage stability of quail eggs pickled in 50% vinegar solution and subsequently stored in glass jars with pickling solution or in flexible pouches without the solution at mean ambient (24°C, 58% RH) and refrigeration (5°C, 80% RH) temperatures was investigated. Pickle solution, egg white and yolk reached equilibrium pH (4.26–4.31) within 2 and 5 days of ambient and refrigeration storage, respectively. Eggs lost up to 12.2 and 8.8% of their weight within 48 h of ageing under ambient and refrigeration storage, respectively. Polypropylene (PP)-packed pickles suffered maximum weight loss followed by high-density polyethylene (HDPE)-packed eggs; losses were negligible in polyester/foil/polyethylene (PFP) laminate-packed samples. A decrease in phosphatidyl choline and phosphatidyl ethanolamine with simultaneous increase in lysophosphatidyl choline and lysophosphatidyl ethanolamine plus sphingomyelin occurred in pickled eggs during storage. Thiobarbituric acid (TBA) value increased and sensory quality declined with storage time. Aerobic plate counts remained fairly low throughout storage. HDPE (84 μm) was found to be an economic and efficient alternative packaging to glass jar for storage of pickled eggs without the pickle solution for up to 4 and 12 months of ambient and refrigerated storage, respectively.     

中国传统油炸食品——麻花的包装与保存技术研究

本文研究了中国传统油炸食品“麻花”的水分吸附等温线,比较了聚丙烯薄膜(以下简称CPP)和金属化聚酯/聚乙烯复合薄膜(以下简称M—PET/PE)包装麻花的保存试验。同时研究了麻花的真空包装和普通包装效果,评估了包装样品的水分得失及货架期。     

Modified Atmosphere Packaging of “Napoleon” Cherry: Effect of Packaging Material and Storage Time on Physical,Chemical, and Sensory Quality

Effects of modified atmosphere and polymeric packaging material on the physical (mass loss, color, firmness), chemical (pH, total titratable acidity, total soluble solid, total phenolic content, total anthocyanin content), and sensory quality of “Napoleon” cherry (Prunus avium L. “Napoleon”) were studied. While lightness (L*) remained fairly unchanged, redness (a*), yellowness (b*), and chroma (C*) decreased during a 42-day storage period, resulting in darker fruit. Firmness did not differ significantly from the initial values (P ≤ 0.05) after 42 days of storage at 0°C. pH increased for all treatments over the storage period. In general, total titratable acidity increased during the first 2 weeks, and then decreased afterwards. Packaging significantly reduced mass losses, which were 24.08%, 0.50%, 0.39%, and 0.81% for control (unpackaged), polypropylene tray/biaxially oriented polypropylene film (PP/BOPP), polypropylene tray/cast polypropylene film, and polyvinyl chloride-polyethylene tray/polyethylene terephthalate-polyethylene films, respectively. Modified atmosphere packaging was found beneficial on extending the shelf life of fruit during storage. The shelf life of “Napoleon” cherries was suggested as 28 days for packaged samples and 14 days for unpackaged samples at 0°C. Samples packaged with PP/BOPP under 21% O₂ 79% N₂ preserved their physical, chemical, and sensory quality better than other treatments.     

Sensory and microbiological quality of shiitake mushrooms in modified‐atmosphere packages

The aim of the present work was to study the influence of modified‐atmosphere packaging on the microbiological and sensory quality of shiitake mushrooms (Lentinula edodes). Mushrooms were packaged under atmospheric air (passive modified atmosphere) and an initial gas mixture of 5% O₂ and 2.5% CO₂ (active modified atmosphere), in bags of two different films: low‐density polyethylene (PE) and polypropylene (PP). As control, mushrooms were packaged in macroperforated PP films. Bags were stored at 5 °C for 20 days. Package atmosphere composition, mushroom respiration rate, weight loss, microbiological counts and sensory quality were determined during storage. Risk assays were also performed. Under the studied conditions, shiitake mushroom deterioration was not due to microorganism growth, and therefore the shelf‐life of this product might be defined by changes in its sensory characteristics. Sensory analysis showed that mushrooms stored under modified atmosphere (active and passive) had a higher deterioration rate than those stored in PP macroperforated films, and lower sensory quality values during the entire storage time. These results suggest that mushroom deterioration was probably due to shiitake mushrooms' sensitivity to high CO₂ concentrations. Copyright © 2007 Society of Chemical Industry     

Effect of storage conditions and packaging materials on the quality attributes of gluten-free extrudates and cookies made from germinated <Emphasis Type="Italic">chenopodium</Emphasis> (<Emphasis Type="Italic">Chenopodium album</Emphasis>) flour

This study evaluated the effect of storage and packaging materials on the quality attributes of germinated C. album flour extrudates and cookies. For the storage studies of the extrudates low density polyethylene (LDPE) and laminated pouches (LP) of polyester-aluminium-polypropylene (PE-AL-PP) and for cookies LDPE and LP of metalized polyester polyethylene (MET-PPE)were used at ambient temperature (25?±?2?°C). Quality parameters like moisture content, water activity, free fatty acids, peroxide value, bulk density, color, hardness, microbial and sensory analysis of developed products were evaluated at an interval of 15 days during 4 months of storage period. Higher quality changes were observed in extrudates and cookies packed in LDPE than in LP and MET-PPE. The overall acceptability data showed higher decrease in the sensory scores of extrudates and cookies packed in LDPE (7.9–5.5 for extrudates and 7.75–5 in cookies) as compared to LP (7.9–6.12 for extrudates) and MET-PPE (7.75–6.10 for cookies) packages. From the above study and results, it is suggested that the LP for extrudate and MET-PPE in cookies can be used for their storage upto 4 months at ambient conditions.     

Effect of storage conditions on the quality of smoke-dried herring (Sardinella eba)

Samples of freshly smoked herring (Sardinella eba) at 140 g kg^?1 moisture were stored for a maximum period of 6 months using five different storage methods: in polyethylene bags at ambient temperature with and without desiccant, frozen ( ?20°), as well as the traditional and a modified oven storage technique. Their relative effectiveness in preserving the quality of the fish was evaluated in terms of storage losses, sensory changes and decomposition. Next to frozen storage, the most effective method was the modified procedure which gave storage yields of 97% and high sensory scores. Proteolytic and lipolytic deterioration was negligible. Although the traditional storage retained high sensory and chemical properties, over 30% storage losses were recorded. Storage in polyethylene bags at ambient temperature was ineffective, while inclusion of desiccant only delayed total decomposition beyond one month. Major organisms observed in stored smoked herring were Micrococcus, Bacillus, coryneform group, Aspergillus, Penicillium, Rhizopus and yeasts.     

Effects of type of packaging material on physicochemical and sensory characteristics of deep‐fat‐fried banana chips

A storage study of deep‐fat‐fried banana chips was carried out for 8 weeks at ambient temperature (27 °C), using four types of packaging material: laminated aluminium foil (LAF), oriented polypropylene (OPP), polypropylene (PP) and low‐density polyethylene (LDPE). The physicochemical and sensory characteristics of the stored banana chips were analysed at weeks 0, 2, 4, 6 and 8. The quality parameters determined were moisture content, water activity (a_w), thiobarbituric acid‐reactive substances (TBARS), texture (breaking force), colour and sensory attributes. The moisture content, a_w, TBARS and breaking force values of all samples increased during storage. The colour also changed during storage, showing higher L and lower a and b values. Samples packed in LAF had the lowest moisture content, a_w, TBARS and breaking force values. The most notable sensory change that occurred during storage was a decrease in crispness. Samples packed in LAF had higher scores than the other three samples, whilst LDPE gave the lowest scores for crispness as well as product colour. There were no significant differences (P > 0.05) in rancid odour among samples packed in OPP, PP and LDPE. However, there were significant differences (P < 0.05) between samples packed in LAF and the other three samples, with LAF giving the lowest rancid odour. © 2002 Society of Chemical Industry     

Maintaining quality of wild vegetables (Aster glehni and Aruncus dioicus var. kamtschaticus) from Ulleungdo(Island), Korea by modified atmosphere packaging

Wild vegetables, Aster glehni and Aruncus dioicus var. kamtschaticus, produced from Ulleungdo (Island), Korea were packaged with 30 μm polypropylene (PP), 30 μm antifogging oriented polypropylene (A-OPP), 30 μm microperforated antifogging oriented polypropylene (MiA-OPP), 30 μm macroperforated low density polyethylene (Ma-LDPE), and 20 μm macroperforated high density polyethylene (Ma-HDPE), stored at 4, 10, and 20°C. Concentrations of O₂ and CO₂ in the packages were not modified by Ma-LDPE and Ma-HDPE. Weight loss was retarded by PP, A-OPP, MiA-OPP, especially as storage temperature decreased. Soluble solids were not affected by packaging materials. pH slightly decreased in LDPE and Ma-HDPE. Appearance, color, and overall acceptability of both vegetables stored at 4°C in PP or MiA-OPP showed the highest sensory score. These results suggest that packaging with PP or MiA-OPP films and storage at 4°C could be a useful method to maintain quality of the wild vegetables.     

Storage quality of powdered cyanobacterium —Spirulina platensis

The cyanobacteriumSpirulina platensis, produced at the Central Food Technological Research Institute, was dried using the cross-flow technique and subsequently subjected to packaging studies. The moisture sorption studies at 27 °C indicated a critical moisture content of 12.5%, corresponding to 56% relative humidity (RH). The product was packed in pouches made of polypropylene (37 μm thick) and a laminate of metallized polyester with low-density polyethylene and was stored at: (1) 38 °C, 90% RH (accelerated condition) or (2) 27 °C, 65% RH (standard condition). Periodically throughout its storage under these conditions, the product was analysed for its content of moisture, protein, ash and fat. In addition, determinations were made of the changes in the constituents carotene, phycocyanin and allophycocyanin.     

QUALITY OF NUGGETS PREPARED FROM FRESH AND SMOKED SPENT LAYER CHICKEN MEAT

Nuggets were prepared from fresh and smoked meats of spent layer chicken of age approximately 18 months, packed in polyethylene bags and stored at -18 ± 2C for 6 months. Thawed nuggets were fried on hot pan coated with refined sunflower oil and product quality was evaluated. Nuggets from smoked chicken had lower (P ± 0.05) moisture and higher fat contents and lower weight loss on frying compared to fresh meat nuggets. Free fatty acid (FFA expressed as percent of oleic acid) increased from 3.6 to 3.9 and 3.2 to 3.7, and thiobarbituric acid (TBA) values (mg malonaldehyde/kg sample) increased from 0.90 to 1.19 and 0.63 to 0.71 for fresh and smoked meat nuggets, respectively, during frozen storage for 6 months. Shrinkage in product diameter on frying ranged from 4.6 to 5.0%. Warner-Bratzler shear values ranged from 0.89 to 1.28 lbs for all products stored frozen up to 6 months. Sensory quality scores for smoked meat nuggets were significantly (P ± 0.05) higher, except for juiciness (P ≥ 0.05), than for fresh meat nuggets. Smoked chicken meat produced better nugget products compared to fresh meat as indicated by lower FFA and TBA values and better sensory quality attributes. Products packed in polyethylene bags can be stored at -18 ≥ 2C for up to 6 months without marked deterioration in product quality.     

Quality and storage life of par-baked frozen breads

During storage of frozen par-baked breads for a prolonged period of time, bread quality may undergo changes such as increased firmness, moisture and flavour losses resulting in product deterioration. Four categories of par-baked breads namely—variety, white, multi-grain and rye were stored at −18°C for 9 months to evaluate the effects of storage period on product quality, and to develop prediction models that describe kinetics of deterioration of selected quality parameters. The quality was evaluated based on sensory, chemical and physical attributes and properties. Storage life was determined based on the changes in bread quality below certain level. The principal component analysis indicated that approximately 90% of the total variability of 19 quality parameters can be explained with only two principal components. The zero-order kinetic reaction showed good agreement (R²>80%) with quality changes observed by the sensory panel over the storage period. A prediction model, based on the bread quality at zero time and the quality at the time when the bread was rejected by the sensory panel, was developed. The proposed prediction model would provide a useful means of estimating storage life of par-baked breads made with similar formulations.     

Effect of Pretreatments on Quality Characteristics of Dehydrated Ivy Gourd (Coccinia indica L.)

Ivy gourd (Coccinia indica L.) is an important tropical vegetable cultivated in India. It belongs to the Cucurbitaceae family and is attributed with neutraceutical properties such as hypoglycemic effect and contained a fair amount of ascorbic acid. The effect of blanching and different pretreatments on the quality characteristics of dehydrated ivy gourd slices was optimized. The treated ivy gourd slices were dehydrated in a cross flow hot air drier at 50 ± 1 °C to a final moisture content of 4.6%. The dehydration ratio of dried ivy gourd slices ranged from 17.1:1 to 18.7:1. Ivy gourd slices blanched at 98 °C in water, dipped in 0.2% potassium metabisulphite (K₂S₂O₅) solution and dried at 50 ± 1 °C for 5–6 h resulted in best product. Dehydrated ivy gourd slices obtained from the optimized treatment had good color, texture with rehydration ratio of 1:8.6. Equilibrium relative humidity of dehydrated slices was 34.18% with an initial moisture content of 4.6% at 28 ± 1 °C. Dehydrated slices were packed in low density polyethylene (LDPE) and metallized polyester polyethylene (MPP) pouches and stored at room temperature (27–35 °C) for 6 months. The dehydrated slices were analyzed for changes in physicochemical composition and sensory quality characteristic such as color and appearance, texture and overall quality during storage. Dehydrated ivy gourd slices remained acceptable during storage of 4 and 6 months in LDPE and MPP pouches, respectively, at room temperature.     

QUALITY OF MINIMALLY PROCESSED LETTUCE AS INFLUENCED BY PACKAGING AND CHEMICAL TREATMENT

Shredded lettuce was packaged in sealed bags of monooriented polypropylene (OPP) film and also in polyethylene (PE) trays overwrapped with a multilayer polyolefin (RD106) or plasticized polyvinyl chloride (PVC) film; and stored at 4C in a refrigerated case during 8 days. Chemical treatment by dipping in a 0.3% ascorbic acid /0.3% citric acid solution did not significantly affect changes in microbial populations or visual sensory attributes. Type of package was not a significant factor for microorganism populations, but was significant (p<0.001) for changes in gas composition and visual sensory attributes. The modified atmosphere within the packages changed from normal air composition to about 1.5% O₂/12% CO₂ for OPP bags and to about 17–18% O₂/1–2% CO₂ for PVC-PE trays and RD106-PE trays after 8 days of storage. The visual sensory quality of the product was retained better in OPP bags than in the other ones.     

Sulphur dioxide evolution during dried apricot storage

Sulphur dioxide is used as a pre-treatment to facilitate drying, improve product quality and extend the shelf life of apricots. During storage, SO₂ losses are observed, thus reducing the effect of this agent. The aim of this paper is to analyze the evolution of SO₂ content in dried apricots packaged in different types of containers, namely glass and polypropylene trays thermosealed with different films (oriented polyamide OPA + polyethylene PE and polyamide PA + polypropylene PP). The packaging atmosphere was air in all cases. Storage was carried out at constant temperature: 5, 15, 25 and 35 °C. Stored samples were analysed periodically over 12 months. In order to model the SO₂ losses, two empirical kinetic models were tested: these models assimilate this process to a first order irreversible and a first order reversible kinetics. The explained variance being higher than 94% in all cases, but only the reversible kinetics is able to depict the residual SO₂ observed.     

The storage life of packed shredded Iceberg lettuce dipped in glycine betaine solutions.

The effects of glycine betaine dip, packaging method, and storage time on the sensory quality of shredded Iceberg lettuce were first modeled using a statistical experimental design, followed by a second storage test verifying the effect of the glycine betaine treatment. Shredded lettuce was dipped in 0 to 100 mg/liter active chlorine solution and then in 0 to 1.0 mol/liter glycine betaine solution, packed in 25 microm oriented polypropylene film, 250 g per package, and stored at 5 degrees C for 8 days. Models with good predictability were created suggesting that the glycine betaine dip helped retain sensory quality, especially appearance (P < 0.05). The models also suggested that washing periods over 60 s were not needed and that the microperforation of packages should not exceed 0.31 mm2 per package. The modeled positive effect on sensory quality was verified in the second storage test (P < 0.05). The optimum glycine betaine concentration was 0.2 mol/liter. Chlorination of the first dip particularly retained appearance of packed lettuce.     

Impact of preservation and different packaging conditions on the microbial community and activity of Kefir grains

Kefir is a cultured milk product that is produced by a mixed acidic and alcoholic fermentation by microbes found within Kefir grains. The aim of this study was to evaluate three different packaging materials in their ability to retain the viability and activity of the grains over an extended storage period. The impact of the different packaging and storage conditions on the microbial community of the grains was also determined. Kefir grains were lyophilized, packaged in three different packaging materials, including low-density polyethylene film (LDPE), oriented polyester film (OPET), and methallized oriented polyester film (MOPET) and stored for 3 months at room temperature. Activity tests, including pH, titratable acidity (%TA), lactose and lactic acid content over a 10 and 18 h fermentation period were used to evaluate the acidification activity of the lyophilized grains. Selective media, morphology and physiological characteristics were used to obtain the enumeration values and to identify the microbes present in the packaged and stored grains. Overall, the best retention of the fermentation activity was found for the MOPET film. The OPET packaging film provided the best preservation of the microbial composition.     

Effect of packaging on shelf-life of minimally processed Bok Choy (Brassica chinensis L.)

Different methods of packaging were investigated for their effectiveness in inhibiting quality deterioration of minimally processed Bok Choy (Brassica chinensis L.). Modified atmosphere packaging (MAP) flushed with 5% O₂ and 2% CO₂ resulted in a reduction of respiration rate and ion leakage of minimally processed Bok Choy stored at 10 °C. The chlorophyll content and F_v/F_m value of minimally processed Bok Choy in MAP decreased much slowly than those of Bok Choy sealed directly in polyethylene (PE) bag or in perforated oriented polypropylene (POPP) bag. Weight loss of Bok Choy in MAP and sealed directly in PE were only 1.3%, while that in POPP reached a high value of 11% during the storage of 10 days. The shelf-life of minimally processed Bok Choy in MAP, sealed directly in PE and in POPP bag at 10 °C were 10, 6 and 4 days, respectively, according to the sensory quality evaluation.     

Quality of Textured Soya Protein During Storage in Different Packaging Materials

Abstract

The shelf stability of textured soya protein (TSP) procured from a single source and packaged in seven different packaging materials [viz. low density polyethylene (LDPE), HDPE, and polypropylene (PP) of 300 and 500 G and HDPE–LDPE–HDPE] in quantities of 10 kg each and stored at three different climatic conditions (viz hot and dry—Jodhpur; hot and humid—Tezpur; normal Mysore) for one year was studied. At the end of 6, 9, and 12 months, samples were drawn and analyzed for the quality parameters like moisture, browning, thiobarbituric acid reactive substances (TBARS), uric acid, water holding capacity (WHC), available lysine, in vitro digestibility, and sensory attributes. Anti nutritional factors like trypsin inhibitor activity (TIA) and phytic acid were also evaluated. The changes in the moisture content and non‐enzymatic browning correlated well with the relative humidity of the place of storage. However the TBARS showed wide variations while the WHC varied between 2.6 and 2.9 of water/g material. Interestingly the TIA showed a ten‐fold decrease (6.65 vs. 0.68 mg/g). The reduction in available lysine (6.33 vs. 5.29/16 g N) correlated well with the observed reduction in in vitro digestibility (84% vs. 73%). Although the sensory quality showed a decline by the end of 12 months storage period, the overall acceptability of the product on the 9 point Hedonic scale, remained very good. It is inferred from the present study that packaging of TSP in HDPE‐500 Primary Sac and HDPE woven Secondary Sac, keeps the product shelf stable up to one year even under diverse climatic conditions.