Changes of physicochemical and sensory characteristics of packed ripe table olives from Spanish cultivars during shelf‐life

Changes in the physicochemical and sensory characteristics of commercial plain (whole) and pitted ripe olives of the Gordal, Manzanilla, Hojiblanca and Cacereña cultivars were studied during a three‐year period in conditions that mimicking the storage of such products in real life. No spoilage was developed during this period. Throughout the shelf‐life, the pH of the cover brines had a marked valley decrease at the beginning of storage followed by a progressive further decline, the surface colour (measured instrumentally) and firmness of the olives followed a first‐order kinetic decay, mitigated according to the iron and calcium contents. Also, a slight browning of the cover brines at the beginning of the storage was observed. No significant changes in most of the sensory characteristics were observed by the panel test during shelf‐life except for a limited change in olive surface colour. At the end of the shelf‐life, most of the samples were classified as ‘extra’ category according to the IOC sensory evaluation method and only plain Gordal presentation was classified as ‘first, choice or select’.     

Effect of cut‐type on quality of minimally processed papaya

BACKGROUND: This research was undertaken to study the effects of different cut‐types (cube, parallelepiped, cylinder and sphere) on the quality and shelf‐life of papaya cv. Sunrise Solo. Physicochemical analyses were carried out during 10 days of storage at 4 °C to determine colour, firmness, pH, titratable acidity, total soluble solids, weight loss and vitamin C content. Microbiological analysis and sensory evaluation were also performed. RESULTS: Papaya spheres (1.55 cm radius) presented the most favourable physicochemical and microbiological properties (smaller changes in colour parameters L*, a*, b*, chroma and hue angle, firmer texture, lower increase in pH, higher titratable acidity, almost constant total soluble solids, reduced weight loss, high vitamin C content and lower microbial loads) and sensory characteristics on day 10, while papaya cubes (1.4 cm side) proved to be the least acceptable. CONCLUSION: The results of physicochemical, microbiological and sensory analyses performed on different cut‐types of papaya indicated acceptable fresh‐cut produce during 10 days of storage at 4 °C. The potential shelf‐life at 4 °C is therefore 10 days, provided that no contamination occurs in the postharvest period and during minimal processing operations. Copyright © 2008 Society of Chemical Industry     

Effect of different packing treatments on the microbiological and physicochemical characteristics of untreated green olives of the Conservolea cultivar

Microbiological, physicochemical and organoleptic changes were studied in non‐pasteurised samples of untreated green olives cv Conservolea stored at 20 °C for 180 days under different preservation treatments (acidified brine and modified atmospheres). The microbial flora consisted of lactic acid bacteria and yeasts, while no enterobacteria and pseudomonads were enumerated in any package. Although no thermal treatment was applied to the packages, no sediment formation was observed due to the growth of propionic bacteria. Olives packed in brine supplemented with 0.3% lactic and 0.3% citric acids presented the highest acidity, the lowest brine and flesh pH and the lowest dark brine colour as measured by the parameter A₄₄₀?A₇₀₀. Olives packed in modified atmospheres (vacuum, 40% CO₂/30% O₂/30% N₂ and air) presented a progressive loss of fruit firmness and colour with time. At the end of the storage period, olives packed in aerobic conditions and 40% CO₂/30% O₂/30% N₂ presented the lowest firmness and skin colour and were unacceptable to the panellists. The best quality characteristics were maintained in vacuum‐packed olives, as indicated by the higher organoleptic scores. Firmness degradation followed first‐order kinetics (r² > 0.980) and the expected shelf‐life was 23, 15 and 9 months for olives packed in vacuum, 40% CO₂/30% O₂/30% N₂ and air respectively. Copyright © 2004 Society of Chemical Industry     

Development of colour and firmness in strawberry crops is UV light sensitive, but colour is not a good predictor of several quality parameters

BACKGROUND: Strawberry ( Fragaria × ananassa Duchesne var. Elsanta) plants were grown in polytunnels covered with three polythene films that transmitted varying levels of ultraviolet (UV) light. Fruit were harvested under near‐commercial conditions and quality and yield were measured. During ripening, changes in the colour parameters of individual fruit were monitored, and the accuracy of using surface colour to predict other quality parameters was determined by analysing the correlation between colour and quality parameters within UV treatments. RESULTS: Higher exposure to UV during growth resulted in the fruit becoming darker at harvest and developing surface colour more quickly; fruit were also firmer at harvest, but shelf life was not consistently affected by the UV regime. Surface colour measurements were poorly correlated to firmness, shelf life or total phenolics, anthocyanins and ellagic acid contents. CONCLUSION: Although surface colour of strawberry fruits was affected by the UV regime during growth, and this parameter is an important factor in consumer perception, we concluded that the surface colour at the time of harvest was, contrary to consumer expectations, a poor indicator of firmness, potential shelf life or anthocyanin content. Copyright © 2011 Society of Chemical Industry     

Physiological and biochemical changes of different fresh-cut mango cultivars stored at 5 °C

Treatments to inhibit browning, decay and to extend shelf life of ‘Keitt’, ‘Kent’ and ‘Ataulfo’ mango cultivars as a fresh‐cut produce were investigated. Combinations of calcium chloride (CaCl₂), antioxidants [ascorbic acid (AA), citric acid (CA)] and two commercial film coatings resulted in a reduction of browning and deterioration of fresh‐cut mangoes stored at 5 °C, especially for the Ataulfo cultivar. The use of CaCl₂ + AA + CA significantly reduced colour deterioration, loss of firmness and did not affect sensory characteristics of fresh‐cut mango, with a larger effect in the Ataulfo cultivar. In general, these treatments prevented loss of sugar and vitamin C of cubes during storage at 5 °C. Shelf life of this cultivar was 21 days, while that of Keitt and Kent was only 9 and 12 days, respectively. There is a correlation between carotene and vitamin C content of Ataulfo mango and its longer shelf life compared with the other cultivars.     

Radiation processing of minimally processed sprouts (dew gram and chick pea): effect on sensory,nutritional and microbiological quality

Sprouts have become an important part of the diet because of their nutritive value and low‐calorie content. The effect of radiation processing (1 and 2 kGy dose) on minimally processed dew gram and chick pea sprouts with respect to different quality parameters was studied over a storage period of 16 days at 8 °C. Radiation treatment and storage period did not have any significant effect on the sensory as well as nutritional qualities of irradiated dew gram and chick pea sprout. No significant change (P > 0.05) was observed in the colour and firmness of irradiated sprouts as compared to control samples. However, radiation processing resulted in significant reduction in aerobic plate counts (APC), coliform counts (CC), yeast and mould count (YMC) and staphylococci counts (SC). Radiation processing of dew gram and chick pea sprouts at 1 and 2 kGy extends the shelf life without affecting sensory and nutritional qualities.     

Shelf life stability of red‐fleshed plum nectars: role of polyphenol fortification on quality parameters

The effect of polyphenol fortification of red‐fleshed plum nectars by addition of plum skin extract on the stability of quality, defined in terms of sensory attributes, phenolic composition and antioxidant activity, during shelf life storage was investigated. The sensory attributes were stable throughout the 3‐month storage period at 5 °C for the control and fortified formulations. Among the phenolic compounds measured only the anthocyanins decreased during the storage period; however, the total antioxidant activity was not affected. The loss of red colour was less pronounced compared to the loss of anthocyanins for both formulations. This might be attributed to enhanced co‐pigmentation as the content of the co‐pigment, neochlorogenic acid, increased, while flavonols remained stable during storage. Polyphenol fortification enhanced the retention of red colour, polyphenol content and total antioxidant capacity compared to the control formulation.     

Application of a check‐all‐that‐apply question for the evaluation of strawberry cultivars from a breeding program

BACKGROUND: Traditionally, breeding research has been focused on increasing yield and fruit size, improving resistance to diseases, behaviour during transport and increasing postharvest shelf‐life. However, consumers' liking is one of the biggest challenges for strawberry breeding programs. In this context, the aim of the present work was to evaluate the application of a check‐all‐that‐apply (CATA) question to study consumers' perception of new strawberry cultivars. RESULTS: Average liking scores were low for a highly appreciated product like strawberries, which could be explained considering unfavourable weather conditions prior to harvest. However, despite the small differences in overall liking scores, significant differences were found in the frequency in which 14 out of the 22 terms of the CATA question were used to describe samples. This suggests that the evaluated CATA question was able to detect differences in consumers' perception of the sensory characteristics of the evaluated cultivars. Moreover, a significant correlation was found between laboratory analyses (firmness, colour, soluble solids and acidity) and consumers' responses to the CATA question, which indicates their validity. CONCLUSIONS: Considering results from the present study, the use of CATA questions could be a simple and interesting methodology to gain insight into consumers' perception of different fruit cultivars. Copyright © 2010 Society of Chemical Industry     

Quality attributes and their relations in fresh black ripe ‘Kalamon’ olives (Olea europaea L.) for table use – phenolic compounds and total antioxidant capacity

Quality attributes were investigated in fresh Greek black table ‘Kalamon’ olives prior to processing. Fruit weight, dimensions, respiration and ethylene production rates, firmness, peel colour, moisture, oil content, total antioxidant capacity (TAC), the concentration of total phenolics (TP) and phenolic compounds (hydroxytyrosol, oleuropein, tyrosol, verbascoside, luteolin‐7‐O‐glucoside, luteolin, rutin) were determined in olives from different orchards. There was a significant effect of orchard on most attributes, but not on fruit firmness. Verbascoside, oleuropein and hydroxytyrosol were the major phenolics, and the presence of verbascoside in ‘Kalamon’ olives is revealed for the first time. Positive correlations were found among fruit weight, dimensions, respiration and ethylene. TAC was positively related mainly to TP, hydroxytyrosol, verbascoside and rutin, but inversely to oleuropein. Luteolin was inversely related to luteolin‐7‐O‐glucoside. Colour darkening was directly related to TAC, while colour parameters were positively and moderately affected by oil and moisture.     

Effects of TiO2–UVC photocatalysis and thermal pasteurisation on microbial inactivation and quality characteristics of the Korean rice‐and‐malt drink sikhye

Sikhye is a popular Korean rice‐and‐malt drink. This drink is prepared using a specific traditional process and has short shelf life. Commercial processing using ultra‐high temperature affects characteristic colour and flavour attributes and disturbs the traditional method of sikhye preparation. The objective of this study was to compare the effect of TiO₂–UVC photocatalysis (TUVP) nonthermal processing with heat‐pasteurised and untreated sikhye samples during storage at 4 and 10 °C. TUVP and heat treatments were both sufficient to inhibit regrowth of total aerobic bacteria and coliform during storage. Hunter colour parameter values showed that the colour of sikhye was less affected by TUVP treatment compared to the heat treatment. Higher sensory scores for flavour, taste and overall preference were attained for low‐dosage TUVP‐treated (0.24 J cm^?2) samples than for heat‐treated samples but without a significant difference. TUVP treatment effectively controlled the microbial growth during storage at 4 °C for more than 18 days which was reported a serious microbiological safety issue. In summary, TUVP showed its suitability for commercialisation possibilities of fresh sikhye drink by inactivating the main micro‐organisms and thus increasing significantly its shelf life with minimum impact on quality characteristics.     

Quality of mango fruits during storage: effect of synthetic and eco‐friendly films

Mango (Mangifera indica) cv ‘Alphonso’ fruits, harvested 40–50 days after flowering, were stored at 27 ± 1 °C and 65% RH under three conditions of packaging: (1) perforated plastic boxes, (2) wax lined cartons sealed with low‐density polyethylene (LDPE) film, and (3) wax lined cartons sealed with chitosan films. The weight loss, firmness, Hunter colour values and acidity were determined periodically during storage. Sensory analysis was carried out to determine colour, firmness, flavour qualities and also defective spots. Principal component analysis (PCA) of the results indicated that fruits stored in perforated plastic boxes and LDPE film‐sealed cartons differed significantly with respect to mango flavour, firmness and development of defective spots, while those in chitosan film sealed cartons retained the desirable qualities for a longer period (up to 20 days) without developing defective spots. The higher level of carbon dioxide and lower level of oxygen, or lower rate of oxygen transmission, associated with chitosan films delay ripening, and the higher water vapour transmission rate minimizes the rate of transpiration and prevents condensation of water droplets on the film. This helps in establishing equilibrium moisture content of mangoes in the cartons, which, in turn, extends the shelf life of fruits for a longer period. Copyright © 2004 Society of Chemical Industry     

Quality aspects of fresh‐cut ‘long‐storage tomato’ as affected by package,calcium chloride and storage time

In this research, some quality changes during storage at 4 °C were assessed in fresh‐cut fruits of a ‘long‐storage tomato’ landrace, packaged in biocompostable materials (PLA Ingeo tray/NatureFlex? film) or in conventional plastics (PET tray + polypropylene film). The effects of dipping in CaCl₂ on the shelf‐life extension were also assessed. Plants were cultivated both off‐season (greenhouse) and in‐season (open field). CO₂ and O₂ concentration, fruit weight loss, firmness, colour, microbial load were measured at 0, 4, 7, 12 days of storage. Headspace gas changes and fruit weight loss were minimised in conventional package. BIO package prevented water condensation, led to max 5% weight loss and made fruits less susceptible to spoilage. Dipping in CaCl₂ induced better firmness, especially in biopackage. Off‐season fruits had overall lower quality than in‐season fruits; however, these may contribute to extend the production season, with interesting marketing implications for the agri‐food industry.     

Characterisation of oregano water extracts and their effect on the quality characteristics of cooked pork

The present study characterises oregano water extracts and reports their effects on the shelf life and quality characteristics of cooked pork. Some changes in oregano extract taking place during its thermal treatment were observed. The main volatile compound in the unheated and heated extracts was carvacrol; however, the second major constituent in the unheated extract β-caryophyllene was absent in the heated one. Colour changes during heating were characterised by an International Commission on Illumination (CIE L a b) method. The heated extract better scavenged 1,1-diphenyl-2-picryl hydrazyl radicals, most likely owing to the formation of stronger radical-scavenging derivatives during thermal treatment. The effect of oregano extracts on the shelf life and colour characteristics of stored meat samples in most cases was not significant; however, sensory assessment clearly showed that the addition of extracts had some negative influence on meat flavour and colour.     

Extending the shelf‐life of bananas with 1‐methylcyclopropene and a chitosan‐based edible coating

BACKGROUND: The marketability of bananas over long distances has been limited due to their highly perishable nature and sensitivity to ethylene. To increase the shelf‐life several alternatives have been tested in attempts to maintain quality characteristics. We evaluated the effects of 1‐methylcyclopropene (SmartFresh^SM, 1‐MCP) and a chitosan‐based edible coating (FreshSeal^®, EC), applied alone or combined, on bananas at ripeness stage 3. All fruits were stored for 8 days at 22 °C, 85% RH. Color development, weight loss, firmness, physiological, sensory and chemical variables were evaluated. RESULTS: After 3 days, control and EC‐treated fruits were completely yellow (°Hue = 90), while 1‐MCP treated fruits alone and combined with EC were still showing some green colorations on tips and neck of fingers. After 7 days, fruits treated with the combination (EC + 1‐MCP) reached a Hue value of 90. Firmer fruits were observed with 1‐MCP alone or combined with EC. A decrease of 0.15% titratable acidity and an increase of 8°Brix were observed in all treatments during the experiment. The incidence of sugar spots was delayed and diminished on fruits treated with 1‐MCP either alone or combined. Sensory results showed no adverse effects by using the 1‐MCP or the edible coating. CONCLUSION: The combined treatment of EC + 1‐MCP could be used to extend the commercial life of bananas for up to four more days. Copyright © 2009 Society of Chemical Industry     

Staling of cereal bran enriched cakes and the effect of an endoxylanase enzyme on the physicochemical and sensorial characteristics

Abstract: The staling of cakes enriched with untreated brans and endoxylanase‐treated brans was evaluated by monitoring the changes in physicochemical, thermal, and sensorial properties of cakes during 7‐d storage. Oat and rice bran were treated with different levels (0, 70, and 700 ppm) of an endoxylanase enzyme and added to cakes on 30% flour weight basis. Moisture losses, water activity, crumb firmness, starch retrogradation, and sensorial characteristics were used as staling indicators. Avrami‐type equations were efficiently used for modeling the starch retrogradation kinetics, while linear models most adequately described crumb firming kinetics. Cake staling induced an increase in crumb firmness and enthalpy of amylopectin retrogradation, and a decrease in crumb moisture and sensory quality and acceptability scores of cakes. Oat bran‐containing cakes better maintained their characteristics compared to the ones containing rice bran along the 7‐d storage. Endoxylanase treatment of brans delayed the changes naturally induced during staling in crumb moisture content, amylopectin retrogradation enthalpy, and crumb firmness in the respective cakes. Deterioration of the sensorial characteristics was slower for the cakes containing endoxylanase‐treated brans, as well. The level of endoxylanase treatment did not differentiate significantly (P < 0.05) any of the staling indicators. Overall, this study demonstrated that addition of endoxylanase‐treated brans can result in cakes with improved nutritional characteristics and increased shelf life. Practical Application: The results of the study show the potential of using enzymes to modify underutilized food sources that can be properly incorporated in baked goods, improving their nutritional value, their quality characteristics, and providing longer shelf life. The developed procedure and results can be utilized by the bakery industry to make high fiber and low cost bakery products with improved sensorial characteristics that are appealing to the consumers.     

Storage studies of tomato and bell pepper using eco‐friendly films

Tomato (Lycopersicon esculentum) and bell pepper (Capsicum annuum), packaged in cartons (approximately 0.35 kg per box) covered with either eco‐friendly chitosan film or synthetic petroleum‐based low‐density polyethylene (LDPE) film, were stored at room temperature (27 ± 1 °C) and 65 ± 3% relative humidity (RH). Fruits were withdrawn periodically and changes in physico‐chemical, instrumental and sensory characteristics were analysed. During storage, oxygen levels showed only marginal changes, while CO₂ levels showed a gradual increase, especially so in LDPE film‐covered cartons. The fresh weight loss, colour, firmness, formation of defective spots and shrivelling showed greater changes for unpackaged fruits as well as for those in LDPE film‐covered cartons, in comparison with fruits stored in chitosan film‐covered cartons, which retained many of the desirable attributes. Principle component analysis of data from sensory or instrumental sensory analyses indicated segregation of samples stored under different conditions with respect to both desirable and undesirable attributes. The fruits showed greater deterioration, including the loss of characteristic bell pepper odour, when packaged in cartons covered with LDPE films, while those packaged in chitosan film retained more of the desirable quality attributes for a longer period. Copyright © 2006 Society of Chemical Industry     

Physico‐chemical and sensory attributes in conjunction with multivariate analysis of two potato (Solanum tuberosum L.) cultivars after 90 days of storage: an exploratory authentication study

Two cultivars of potato (Spunta and Agria), were studied in terms of their physico‐chemical and sensory characteristics. These cultivars were cultivated in three geographical regions of Greece (Macedonia, North Greece; Thessaly, Central Greece; Peloponnese, South Greece) and were stored for 90 days after harvesting. The physico‐chemical characteristics of the tubers determined, were pH, total acidity, firmness, dry matter and content in Ν, in Κ, P, Cu, Mn, Zn and Fe. The sensory characteristics measured for raw tubers of potato after storage, were skin colour, skin brightness, internal colour, surface roughness, odour intensity, moistness, surface wrinkling and stains while the sensory characteristics measured for the boiled tubers of potato were odour intensity, moistness, special taste, sweet taste, aftertaste persistence, metal taste, pastiness, mastication, flavour intensity, elasticity and overall acceptability. The application of multivariate analysis (principal component analysis, cluster analysis and discriminant analysis), revealed a variety of relations between the various parameters and resulted in satisfactory grouping either per geographical region or per cultivar.     

Oven‐dried table olives: textural properties as related to pectic composition

The effects of processing treatments on the microscopic structure, pectic fractions and firmness of ripe olives (Olea europaea L Cassanese variety), processed by the ‘Ferrandina’ method for oven‐dried table olive production, were studied. The process included a first heating step, a salting step and a final oven‐drying process. Scanning electron microscopic observations of olive tissue structure revealed that heat treatment was highly damaging, affecting the intercellular pectic substances and producing cell separation. Epicuticular waxes were barely affected and limited the shrivelling of the fruit during the oven dehydration process. The pectin content was higher in the oven‐dried olives than in the fresh samples. The sodium hydroxide‐soluble fraction was the main pectin fraction in the olive tissues. Its content decreased markedly after the heating step, while it increased after the oven dehydration step. The softening of the olive tissues increased after heat treatment, and a correlation was found between protopectin content and firmness. In oven‐dried olives a firming of the olive tissues was observed due to the de‐esterification of pectin and to its decreased solubility resulting from an increase in cell wall calcium bridging. © 2000 Society of Chemical Industry     

Effect of different iron compounds on wheat and gluten‐free breads

BACKGROUND: Iron fortification of bread often results in sub‐optimal quality of the final product due to undesirable changes in the physical characteristics and sensory properties of the bread. In this study both the form of iron (soluble, insoluble or encapsulated) and the type of bread (wheat or gluten‐free) were varied in order to investigate the effect of iron and gluten on the product characteristics. RESULTS: The effect of iron on the quality characteristics of the breads investigated depended on iron type, but not on iron solubility. Colour, crust firmness, specific volume, cell number and uniformity as well as aroma were the attributes that were mainly affected in iron‐enriched wheat bread. In some cases, specific volume was 30% lower than that of the control sample, while cell uniformity was significantly lower, as low as 50% of the control sample in some fortified samples. In gluten‐free breads, differences between unfortified and fortified samples included colour, crust firmness, cell number, ‘moisture’ odour, metallic taste and stickiness. In some cases, the sensory scores were better for fortified samples. CONCLUSIONS: Differences due to iron fortification were less pronounced in gluten‐free compared to wheat breads. The choice of the appropriate iron compound which will not cause adverse quality changes is still a challenge. Copyright © 2010 Society of Chemical Industry     

Influence of hydroponic and soil cultivation on quality and shelf life of ready-to-eat lamb's lettuce (Valerianella locusta L. Laterr)

BACKGROUND: Nowadays, there is an increasing interest in the hydroponic floating system to cultivate leafy vegetables for ready‐to‐eat salads. It is reasonable that different growing systems could affect the quality and shelf life of these salads. RESULTS: The quality and shelf life of ready‐to‐eat lamb's lettuce grown in protected environment in soil plot or in soil‐less system over hydroponic solution with or without the addition of 30 µmol L^?1 silicon were evaluated. Minimum effects were observed on colour, firmness and microbial counts. Hydroponic cultivation largely affected plant tissue hydration, leading to weight loss and structural modifications during refrigerated storage. The shelf life of lamb's lettuce was limited by the development of visually detectable unpleasant sensory properties. Shelf life, calculated by survival analysis of consumer acceptability data, resulted about 7 days for soil‐cultivated salad and 2 days for the hydroponically grown ones. The addition of silicon to the hydroponic solution resulted in an interesting strategy to increase plant tissue yield and reduce nitrate accumulation. CONCLUSIONS: Although hydroponic cultivation may have critical consequences on product quality and shelf life, these disadvantages could be largely counterbalance by increased yield and a reduction of nitrate accumulation when cultivation is performed on nutritive solutions with supplemental addition of silicon. Copyright © 2011 Society of Chemical Industry