The sensory and microbiological quality of fresh sliced mushroom (Agaricus bisporus L.) packaged in modified atmospheres

The effect of modified atmospheres, generated by using different packaging films, on the quality of sliced mushrooms was evaluated. The carbon dioxide and oxygen content inside the packages as well as the colour, texture, weight loss, sensory attributes, mesophiles, psychrotrophs, Pseudomonas fluorescens, faecal coliforms, Escherichia coli and anaerobic spores were determined. Modified atmospheres containing 2.5% CO₂ and 10–20% O₂ reduced the microbial counts and improved the mushrooms’ appearance when compared with an air atmosphere. Modified atmospheres containing 15% CO₂ and <0.1% O₂ inhibited mushroom development and toughening and reduced microbial growth. Although these atmospheres had no effect on colour, they did allow the development of off odours and anaerobic spores were detected. No differences in microbial growth or mushroom spoilage were observed under the different moisture contents generated in the packages at 4 °C. Aerobic bacteria counts were considered very high even at the beginning.     

Effects of UV‐C irradiation on the physiological and antioxidant responses of button mushrooms (Agaricus bisporus) during storage

Novel postharvest technology not only preserves the freshness of fruits and vegetables, but also triggers the biosynthesis of antioxidant compounds as a secondary response. This study examined the browning and antioxidant properties of button mushrooms (Agaricus bisporus) treated with UV‐C irradiation in combination with cold storage. Three sample preparation methods for antioxidant activity analysis, simulative gastrointestinal digestion (GAR), direct evaluation (QUENCHER) and traditional solvent extraction (TSE), were used to evaluate the samples, and followed analysing by both FRAP and ABTS assays. Broadly, the results indicated that, following an initial increase, UV‐C irradiation suppressed browning during a cold storage period of 18 days. And the total phenolic content of the treated mushrooms were higher than that of the control, while the ascorbic acid content decreased sharply during storage, and UV‐C treatment had negative effects on ascorbic acid content. Results from the QUENCHER and GAR methods showed that UV‐C treatment significantly increases the total antioxidant capacity (TAC) of mushrooms throughout the entire storage period, and have a larger magnitude than that of TSE method. In conclusion, the combination of UV‐C irradiation and cold storage showed great potential for improving mushroom quality as a new postharvest technology.     

Calcium chloride irrigation influence on yield,calcium content,quality and shelf‐life of the white mushroom Agaricus bisporus

Seven CaCl₂ irrigation treatments (0.15, 0.25, 0.35, 0.45, 0.55, 0.75 and 1.00%) were applied to the Agaricus bisporus white strain A15 (Sylvan) in order to evaluate, in comparison with the water‐irrigated crop, their effect on production characteristics, ie yield, sporophore number and size mix, average mushroom weight as well as pileus and stipe Ca content. In addition, initial mushroom colour and texture in three successive flushes and their variations during post‐harvest storage for 8 days at 4 °C and for 2 days at 18 °C were determined. Statistical analysis of data revealed that crop yields were not affected by the individual treatments, whereas the mushroom number was reduced and the average sporophore weight was enhanced. A strong positive correlation was established between CaCl₂ dosage and Ca content of fresh mushrooms, which increased considerably in the third flush by accumulating in both pileus and stipe parts (the former containing less Ca than the latter) and presented a maximum for the 0.75 and 1.00% CaCl₂ treatments. At harvest, colour of second‐ and third‐break mushrooms was significantly improved by all CaCl₂ treatments. This beneficial effect was more pronounced after 8 days of cold storage and during shelf‐life in sporophores treated with 0.35, 0.75 and 1.00% CaCl₂. No consistent correlation was found between Ca content and texture of fresh and stored mushrooms. However, although softer mushrooms were recorded at harvest in most CaCl₂‐irrigated crops, 0.25, 0.75 and 1.00% concentrations appeared to retard mushroom softening, promoting firmness at the 8th day of cold storage and during shelf‐life. © 2001 Society of Chemical Industry     

Influence of growth stage and postharvest storage on ascorbic acid and carotenoid content and visual quality of baby spinach (Spinacia oleracea L.)

To investigate the variations in quality with growth stage and postharvest storage, spinach was sown on three occasions. For each occasion, the spinach was harvested at three growth stages at 6‐day intervals. The second stage corresponded to a growth period used for baby spinach by commercial growers. After harvest, the leaves were stored in polypropylene bags at 2 °C or 10 °C. The highest ascorbic acid content in fresh material was found at stage I. During storage, the ascorbic acid content decreased considerably and the dehydroascorbic acid/vitamin C ratio increased. Storage at 2 °C gave a smaller reduction in ascorbic acid content than storage at 10 °C. Total carotenoid content increased or remained stable during storage. Lutein was the major carotenoid, making up about 39% of the total carotenoid content, followed by violaxanthin, β‐carotene and neoxanthin. Visual quality decreased during storage in most cases, and was correlated to initial ascorbic acid and dry matter contents. The initial AA content might therefore be used as a parameter for predicting the shelf‐life of baby spinach. The results also indicate that by harvesting baby spinach a few days earlier than the current commercial stage of harvest the postharvest visual quality and nutritional quality may be improved. Copyright © 2005 Society of Chemical Industry     

Effect of atmosphere composition on the quality of ready‐to‐use broccoli raab (Brassica rapa L.)

BACKGROUND: Many leafy brassicas are widely used for ready‐to‐use salads. Broccoli raab (Brassica rapa L.), also called turnip top, or rapini, is extensively cultivated in southern Italy. The edible portion is made up of the green, immature inflorescences and the stem with its most tender leaves. Recently, interest in this crop has increased among European consumers; moreover, a substantial increase in consumption could come from the ready‐to‐use product. RESULTS: The effects of four different atmosphere compositions (air, 3% O₂ in nitrogen, 3% O₂ + 10% CO₂ in air, and 10% CO₂ in air) on quality attributes of ready‐to‐use broccoli raab were studied. Controlled atmosphere affected appearance, composition, respiration rate, weight loss, and presence of off‐odours. Storage of broccoli raab florets under low oxygen conditions delayed post‐cutting deterioration during storage at 5 °C and preserved appearance and typical odour, up to 17 days. Moreover, respiration rate as well as loss of green colour, chlorophyll and vitamin C were also slowed down in this condition. Finally, in this study no effect of controlled atmosphere storage was found on total phenols content and antioxidant activity. CONCLUSION: Results showed that cold storage in 3% O₂ can be beneficial in order to maintain quality of ready‐to‐use, broccoli raab for up to 17 days. Copyright © 2010 Society of Chemical Industry     

Effect of gamma irradiation on the physico‐chemical and sensory properties of raw shelled peanuts (Arachis hypogaea L.) and pistachio nuts (Pistacia vera L.)

Backround The present study evaluated the quality of raw peanuts and pistachio nuts as a function of irradiation dose in order to determine dose levels causing minimal undesirable changes to these products. Physico‐chemical (colour, peroxide value, hexanal content, fatty acid composition, volatile compounds) and sensory (colour, texture, odour, taste) properties of raw peanuts and pistachio nuts were determined after irradiation at doses up to 7 kGy. Results Results showed an eight‐ and seven‐fold increase in peroxide value and a twelve and five‐fold increase in hexanal content after irradiation at a dose of 7 kGy for peanuts and pistachio nuts, respectively. An increase was also observed in saturated fatty acids (20.51–28.28% and 15.24–24.87%) with a parallel decrease in unsaturated fatty acids (79.49–71.72% and 84.76–75.13%) for peanuts and pistachio nuts, respectively. Likewise, volatile compounds such as aldehydes, alkanes, ketones and alcohols comprising secondary oxidation products of peanut and pistachio nut lipids increased after irradiation. Pistachio nut colour parameter a* and to a lesser extent parameters, L* and b* decreased after irradiation leading to a slight but noticeable darkening in product colour while colour parameter L*, b* and a* of raw peanut remained unchanged by irradiation up to 7 kGy. Conclusion Based on sensory evaluation, peanuts and pistachio nuts become unacceptable for consumption when irradiated at doses higher than 3 kGy. Copyright © 2009 Society of Chemical Industry     

Interactive effect of supplemental ultraviolet B and elevated ozone on seed yield and oil quality of two cultivars of linseed (Linum usitatissimum L.) carried out in open top chambers

BACKGROUND: Current scenarios of global climate change predict a significant increase in ultraviolet B (UV‐B) and tropospheric ozone (O₃) in the near future. Both UV‐B and O₃ can have detrimental effects on the productivity and yield quality of important agricultural crops. The present study was conducted to investigate the individual and interactive effects of supplemental UV‐B (sUV‐B) (ambient + 7.2 kJ m^?2 day^?1) and O₃ (ambient + 10 ppb) on the yield and oil quality of two cultivars of linseed (Linum usitatissimum L.). RESULTS: The mean monthly ambient O₃ concentration varied from 27.7 to 59.0 ppb during the experimental period. O₃ affected fruit formation, while sUV‐B was mainly responsible for ovule abortion. Seed sugar and protein contents showed maximum reduction in O₃‐treated plants, while mineral nutrient levels were most affected by sUV‐B + O₃ treatment. Rancid oil of low nutritional quality and containing long‐chain fatty acids was favoured along with a decrease in oil content. CONCLUSION: sUV‐B and O₃ individually as well as in combination caused deterioration of the yield and quality of oil and seeds of linseed. However, the individual effect of O₃ was more damaging than the effect of sUV‐B or sUV‐B + O₃, and cultivar T‐397 performed better than Padmini. © 2012 Society of Chemical Industry     

Effect of the stage of growth,wilting and inoculation in field pea (Pisum sativum L.) silages. II. Nitrogen fractions and amino acid compositions of herbage and silage

The aim of the study was to investigate the effects of stage of maturity, wilting and inoculant application on proteolysis in field pea herbage and silage in northern Italy. Semi‐leafless field peas were harvested at four progressive morphological stages (end of flowering, I; beginning of pod filling, II; advanced pod filling, III; beginning of ripening, IV). For each stage of growth, the herbage was field wilted to a dry matter (DM) content around 330 g kg^?1. The unwilted and wilted herbages were ensiled with (I) and without (C) a lactic acid bacteria (LAB) inoculant. The stage of growth significantly affected all the nitrogen fraction concentrations both in herbage and in silage. Extensive proteolysis took place in silages made at early morphological stages and characterised by a high crude protein content (around 240 g kg^?1 DM), as shown by the non‐protein nitrogen (NPN) value (around 700 g kg^?1 total N or higher). Neither inoculum nor wilting helped to reduce the protein degradation in these silages. The level of proteolysis was reduced in silages made from the pod filling stage onwards where most of the protein was localised in the seed and a better fermentation pattern was observed. The amino acid (AA) composition of silages made at stage IV was close to that of fresh herbage, with minimal losses of nutritionally essential amino acids for ruminants. Copyright © 2006 Society of Chemical Industry     

Effect of oregano and thyme essential oils on the microbiological and chemical quality of refrigerated (4 °C) ready‐to‐eat squid rings

The efficacy of oregano and thyme essential oils (OEO and TEO, respectively) in the quality retention of a refrigerated (4 °C) squid (Loligo vulgaris) ring ready‐to‐eat (RTE) product was studied. Essential oils were added at different concentrations to the coating medium during processing. An inhibitory (P < 0.05) effect of OEO on the microbial activity (aerobes, anaerobes, Enterobacteriaceae, psychrotrophs) of the squid rings was observed, with a more pronounced effect as OEO concentration increased. The addition of OEO also led to an inhibitory (P < 0.05) effect on lipid oxidation, as determined by peroxide, thiobarbituric acid‐reactive substance and interaction compound formation; however, no effect (P > 0.05) of the OEO concentrations on lipid oxidation development was detected. The addition of TEO did not lead to an inhibitory effect (P > 0.05) on the microbial activity of the refrigerated RTE squid, although a slight inhibitory (P < 0.05) effect on lipid oxidation was observed in the batches including the higher TEO concentrations.     

Effect of washing with tap and treated seawater on the quality of whole scad (<Emphasis Type="Italic">Trachurus trachurus</Emphasis>)

The effects of washing whole scad (Trachurus trachurus) with fresh water and seawater were evaluated. Fish evaluations for 12 days of storage in ice included sensory (EU and the QIM scheme), physical (Torrymeter and Freshmeter) and microbiological changes [counts of total bacterial numbers, specific spoilage organisms (SSO) and Pseudomonas]. The main conclusions are that both kinds of wash influenced physical and microbiological evaluations (mainly on Freshmeter values and counts of SSO). Washes seemed to interfere with properties of the fish skin cells that influenced the instrumental readings. By sensory means, the effects were not detected, resulting in similar shelf-lives, although some slight differences could be observed in mucus brightness in the first 2 days storage in ice. No significant differences were found between washing with tap water and treated seawater, but slightly lower values were obtained initially with seawater, in the first 24–48 h, with the Torrymeter and the Freshmeter.     

Mixed fermentation of jujube juice (Ziziphus jujuba Mill.) with L. rhamnosus GG and L. plantarum-1: effects on the quality and stability

This study was conducted aiming at improving the quality of jujube juice by mixed fermentation of lactobacilli. Selection of favourable lactobacilli and addition of nitrogen sources were explored as an efficient method to improve the viability of probiotic in jujube juice. After fermentation, the viability increased to 9.15 ± 0.10 Log CFU mL⁻¹, while the content of lactic acid increased to 5.61 ± 0.03 mg mL⁻¹. The total phenolic and total flavonoid content were 2663.03 ± 11.95 μg mL⁻¹ and 163.95 ± 0.47 μg mL⁻¹ respectively. Moreover, the stability of fermented jujube juice during refrigeration was investigated, which showed that the viability dropped to 8.84 ± 0.6 Log CFU mL⁻¹ and the concentration of lactic acid slowly increased to 6.51 ± 0.04 mg mL⁻¹; the ABTS value showed a 4.26% reduction and FRAP value did not significantly (P < 0.05) change during refrigerated storage. In addition to the existing knowledge, our data aid to the future applications of the jujube as a potential ingredient in novel probiotic foods formulation.     

Influence of nutrient solutions in an open‐field soilless system on the quality characteristics and shelf life of fresh‐cut red and green lettuces (Lactuca sativa L.) in different seasons

BACKGROUND: Little information is available about the impact of nutrient solution ion concentration on quality characteristics and shelf life of fresh‐cut lettuce grown in soilless systems in open field. Three lettuce genotypes, lollo rosso and red oak leaf as red‐leafed genotypes and butterhead as green‐leafed genotype, were studied. The influence of three nutrient solutions with low, medium and high ion concentrations, which varied in the macroanion (NO$_{3}^{-}$ ) and macrocations (K⁺, Ca²⁺ and NH$_{4}^{+}$ ), were compared in summer and winter. RESULTS: The nutrient solutions evaluated in this study for the production of lettuce in a soilless system did not strongly influence the quality characteristics of the raw material. When the ion concentration of the nutrient solution was increased, fresh weight decreased, although it depended on the genotype and season. Maturity index and dry matter content varied with the season but independently of the nutrient solution. In summer, maturity index was higher and dry matter lower than in winter. Initial texture and visual quality were not influenced by the nutrient solution. Medium ion concentration provided the highest content of vitamin C and phenolic compounds. Our observations pointed out that the genotype had a strong influence on the shelf life of the fresh‐cut product with minor differences among nutrient solutions. In general, red‐leafed lettuces showed the highest antioxidant content, helping the maintenance of sensory characteristics throughout storage. CONCLUSION: The combination of optimal nutrient solution ion concentration and suitable cultivar is considered essential to ensure lettuce post‐cutting life. Copyright © 2012 Society of Chemical Industry     

Effects on growth performance, carcass characteristics, and the fat and meat fatty acid profile of rabbits fed diets with chia (Salvia hispanica L.) seed supplements

The effects of three levels (0%, 10%, or 15%) of chia (Salvia hispanica L.) seed (SHS) included in the diet on the growth performance, some carcass characteristics and fatty acid profile of rabbit meat and perirenal fat was studied. At the end of the experiment, there were no significant differences among the groups in live weight, live weight gain, feed consumption, feed efficiency, carcass yield or the percentages of edible organs. The percentage values of hind legs, fore legs, loin and abdominal wall, breast and ribs, skin and limbs, and head were not affected by the inclusion level of SHS. The polyunsaturated fatty acid (PUFA) concentration in the longissimus dorsi muscle and perirenal fat was significantly increased with increasing SHS inclusion, while the saturated fatty acid (SFA) decreased. The n − 6/n − 3 PUFA ratio of the rabbit meat decreased from 4.55 in the control group, to 1.03 in the 15% SHS group.     

Carcass and meat quality traits of wild boar (Sus scrofa s. L.) with 2n = 36 karyotype compared to those of phenotypically similar crossbreeds (2n = 37 and 2n = 38) raised under the same farming conditions 2: Fatty acid profile and cholesterol

The aim of this study was to compare European wild boar (Sus scrofa) with chromosomal number 2n = 36 to phenotypically similar animals with 2n = 37 and 2n = 38 chromosomes (crossbreeds) with respect to fatty acid (FA) profile and cholesterol content. According to gender and genetic group (2n = 36, 2n = 37, and 2n = 38; seven animals each), the FA profile in longissimus dorsi (LD), semimembranosus (SM) muscles, and back fat was measured. Cholesterol content of LD and SM muscles was also analysed. The animals were fed and reared under the same conditions until slaughter at the age of nine months. FA profiles of LD, SM, and back fat were measured by GC and cholesterol with HPTLC. SM muscle of wild boar group (2n = 36) showed a higher proportion of PUFAs and lower C16:0 and C18:0 than that of crossbreeds. No differences in the FA profiles of LD and cholesterol content of LD and SM muscles among karyotypes were found.     

Effect of treatment with α‐galactosidase,tannase or a cell‐wall‐degrading enzyme complex on the nutritive utilisation of protein and carbohydrates from pea (Pisum sativum L.) flour

The effect of treatment with α‐galactosidase, tannase or a cell‐wall‐degrading enzyme complex under optimal conditions of pH, temperature and length of incubation time on the chemical composition and nutritive utilisation of protein and carbohydrates from pea (Pisum sativum L.) flour was studied. Soaking of pea flours in combination with enzyme treatment led to reductions of 77–90% in the levels of α‐galactosides, and of 60–80% in the levels of trypsin inhibitor activity, increasing the content of total available sugars, which was highest in the pea flour treated with the cell‐wall‐degrading enzyme complex. All the treatments assayed caused a significant improvement in daily food intake, whereas the nutritive utilisation of protein was not increased in any of the pea products tested when compared to the raw pea flour. However, all the soaking and enzymatic treatments led to a significant improvement in daily weight gain associated with a higher dietary intake of food and total available sugars. Copyright © 2007 Society of Chemical Industry