Longer Storage Periods Research Articles

Effects of graded levels of liquid brewer's yeast on chemical composition and fermentation quality in cassava pulp and rice straw-based total mixed ration silage.

This study aimed to evaluate the effect of liquid brewer's yeast (LBY) addition on chemical composition and fermentation quality of mixture of LBY and cassava pulp (CVP) with rice straw (RS) in different ratios during preservation periods. Four mixtures of LBY, CVP and RS were made, that is mixture ratio of LBY : CVP : RS of 0% LBY, 20% LBY, 35% LBY and 50% LBY were 0:70:30, 20:50:30, 35:35:30 and 50:20:30 as fresh matter, respectively. The bags were opened at weeks 0, 1, 2, 4 and 8 after storage. The contents of dry matter, organic matter, crude protein (CP), ether extract (EE), neutral detergent fiber and acid detergent fiber ranged 36.4-40.0, 88.9-90.8, 4.0-12.0, 1.1-1.3, 58.8-61.6 and 37.6-40.0, respectively, and the contents of CP and EE increased and the other components decreased in proportion to LBY inclusion (P < 0.01). 50% LBY had the highest (P < 0.05) pH (4.81) and ammonia nitrogen per total nitrogen (NH3 -N/TN) (7.40%) and the lowest V-score (90.3). Propionic and butyric acid contents were 0.01% or lower in each mixture and storage period. There were rapid pH decrease and NH3 -N/TN increase during the first week of the storage period. The increases of NH3 -N/TN and acetic acid content and decreases of pH, lactic acid content and V-score during the preservation were more drastic as LBY inclusion increased. Although higher proportion of LBY produced higher CP and lower fiber contents in the mixture, attention should be paid for the reduction of fermentation quality during longer storage periods.

Long-term storage does not impact the quality of cryopreserved human ovarian tissue.

BackgroundOvarian tissue cryopreservation is an emerging technique, also addressed to very young cancer patients, for whom it is not possible to perform an ovarian stimulation for oocytes freezing, before gonadotoxic treatment. In this cases, ovarian tissue must be cryopreserved for a long period of time and it is very important to know if it maintains fertility function after a long period of storage. Here we aimed to assess the effect of long-term storage on preservation and viability of cryopreserved human ovarian tissue.MethodsDescriptive study of three cases of cancer patients whose cryopreserved ovarian tissue remained stored for 18 years. Long-term stored tissue was examined by histological and immunohistochemical analysis, transmission electron microscopy, TUNEL assay and LIVE/DEAD viability/citotoxicity test.ResultsOvarian tissue stored for 18 years showed a good morphology. Follicles presented negative staining for estrogen and progesterone receptors, positive staining for ki67 in granulosa cells and/or oocytes and for bcl2 in granulosa cells. Regarding stroma, patch/focal positive expression was found for estrogen receptor and ki67, diffusely positive expression for progesterone receptor and bcl2. After long-term storage, ultrastructural examination showed sub-cellular integrity of follicles and interstitial oedema foci. No apoptosis was observable by TUNEL assay. Stromal cell viability remained >97 % during the culture period.ConclusionThe evaluation of different aspects of the tissue provides evidence that the storage time does not impact on tissue quality and gives hope especially to cancer girls, whose tissues could remain cryopreserved for a very long time.

Comparison of sealing and open conditions for long term storage of corn stover using low-moisture anhydrous ammonia pretreatment method

As a promising material for bioethanol production, corn stover has been studied under various pretreatment methods prior to production of bioethanol. However, the storage of pretreated corn stover is still challenged by both weather conditions and the physical properties of its own. The main objective of this experiment is to evaluate the effect of low-moisture anhydrous ammonia (LMAA) pretreatment method on biomass quality during long periods of storage. In this study, corn stover was contacted with various ammonia loadings (0, 0.1, and 0.2g/g DM biomass) and moisture content (20wt.%, 40wt.%, and 60wt.%) from 1 day to 90 days both in sealed and open containers. As a result, the mass loss in sealed container increased with time; however, the mass loss in open container was affected by the conditions of the environment. In terms of the carbohydrate, no significant reduction was observed in either sealed or open containers.

USO DE REVESTIMENTO COMESTÍVEL PARA EXTENSÃO DA VIDA ÚTIL DA GOIABA ‘PEDRO SATO’

A goiaba possui intensa atividade metabólica, requerendo o uso de tecnologias pós-colheita para extensão de sua vida útil e manutenção da qualidade. Como é fruto que se consome com a casca, a aplicação de revestimento comestível é uma tecnologia de modificação da atmosfera passível de ser implementada. Objetivou-se, com esse trabalho, avaliar índices de qualidade pós-colheita de goiaba ‘Pedro Sato’, tais como vitamina C, licopeno, β-caroteno, glicose, frutose, sacarose, etc., submetida a três diferentes revestimentos comestíveis (à base de amido de mandioca, alginato de sódio ou carboximetilcelulose) e armazenamento refrigerado à 10 oC. Independentemente do tratamento aplicado, as goiabas ‘Pedro Sato’ alcançaram maiores teores de vitamina C após o armazenamento prolongado de 22 dias. Por outro lado, o uso de revestimentos comestíveis à base de amido e alginato foram eficientes em retardar o amadurecimento das goiabas ‘Pedro Sato’ armazenadas por quatro dias sob refrigeração, seguidos de três dias em temperatura ambiente. As goiabas revestidas com amido de mandioca apresentaram os maiores teores de licopeno (ação antioxidante) e de β–caroteno (precursor da vitamina A no organismo humano), nos períodos de armazenamento mais prolongados, podendo-se recomendar este revestimento comestível para o armazenamento desse fruto, para que se obtenha maior retenção de importantes atributos de sua qualidade.

Persistence of bacterial indicators and zoonotic pathogens in contaminated cattle wastes.

BackgroundManure can provide a favourable environment for pathogens’ survival. De-contamination may be conducted by extended storage, until field conditions are suitable for application to land as source of agricultural nutrients.ResultsThe hygienic evaluation of manure and slurry coming from a plant that collects cattle livestock wastes from a big slaughterhouse was carried out. Samples were even collected from spillages in the area around the plant. Microbial analyses highlighted the massive presence of faecal indicators in all samples: mean counts of Escherichia coli and enterococci were always above EU limits for marketable processed manure products.Cultures referable to the genus Brucella spp. were recorded in two samples of fresh manure but not in the aged ones. Conventional isolation techniques failed to detect members of the Mycobacterium genus, while by means of IS900 and F57 PCR real-time system on DNA directly extracted from environmental samples, the pathogen was detected in all cases.ConclusionsThoughtful design of manure storage infrastructure is critical to prevent spills and over-topping of an open structure. The documented overload situation seems to lay the basis for an ongoing environmental contamination by enteric organisms and opportunistic pathogens circuit faecal-oral route. Moreover, the type of wastes analysed during this study, namely a mixture of fresh cattle manure, bedding and rumen content, needs a longer storage period or, alternatively, of specific chemical, biological or thermal treatments for stabilization.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0705-8) contains supplementary material, which is available to authorized users.

Alternatives to sulfuric acid for slurry acidification: impact on slurry composition and ammonia emissions during storage

Acidification of slurry is a treatment known to reduce ammonia emissions and it is currently applied at the farm scale in Denmark by adding concentrated sulfuric acid (H2SO4). However, several risks are associated with the use of this strong acid and therefore an alternative is required to protect the health of farmers and animals. The effects of five different additives at two target pH values, 5.5 and 3.5, on the composition of two different slurries (pig and dairy) were assessed. The evolution of pH and NH3 volatilization from acidified and non-acidified slurries, kept in closed vessels at an ambient temperature of 15 °C, was followed during a storage period of 60 days. Acidification to pH 5.5 with all additives significantly reduced NH3 emissions, and the greatest decreases relative to raw slurry were obtained with H2SO4 (75% in pig and 81% in dairy slurry) and alum (69% in pig and 87% in dairy slurry). Acidification to pH 3.5 reduced NH3 emissions in both slurries to values considered negligible during the whole storage period. However, longer storage periods should be studied to evaluate NH3 evolution and slurry composition in the longer-term. Sulfuric acid and alum were the additives which could be used in the lowest amounts to decrease the pH to 5.5 and were the most efficient in reducing NH3 emissions. Acidification promoted P solubilization, except when alum was used. Nevertheless, this initial solubilization of P when the pH was decreased to 5.5 had been reversed after two weeks of storage. In conclusion, alum can be considered as a good alternative to H2SO4 when the pH is lowered to 5.5, as the amount of this additive used was similar to that of H2SO4 and it was as efficient as H2SO4 with respect to reducing NH3 volatilization during storage.

Use of hydrocolloids as cryoprotectant for frozen foods

ABSTRACTFreezing is one of the widely used preservation methods to preserve the quality of food products but it also results in deteriorative changes in textural properties of food which in turn affects its marketability. Different foodstuffs undergo different types of changes in texture, taste and overall acceptability upon freezing and subsequent frozen storage. Freezing and thawing of pre-cut or whole fruits and vegetables causes many deleterious effects including texture and drip losses. The major problem in stability of ice-cream is re-crystallization phenomena which happens due to temperature fluctuations during storage and finally impairs the quality of ice-cream. Frozen storage for longer periods causes rubbery texture in meat and fish products. To overcome these problems, hydrocolloids which are polysaccharides of high molecular weight, are used in numerous food applications involving gelling, thickening, stabilizing, emulsifying etc. They could improve the rheological and textural characteristics of food systems by changing the viscosity. They play a major role in retaining texture of fruits and vegetables after freezing. They provide thermodynamic stability to ice cream to control the process of re-crystallization. Hydrocolloids find application in frozen surimi, minced fish, and meat products due to their water-binding ability. They are also added to frozen bakery products to improve shelf-stability by retaining sufficient moisture and retarding staling. Various hydrocolloids impart different cryoprotective effects to food products depending upon their solubility, water-holding capacity, rheological properties, and synergistic effect with other ingredients during freezing and frozen storage.

Effect of chilled and freezing pre-treatments prior to pulsed electric field processing on volatile profile and sensory attributes of cooked lamb meats

Abstract This research aimed to gain better understanding on the effects of chilling and freezing prior to pulsed electric field processing (PEF) on volatile profile and sensory attributes of different cooked lamb muscles (i.e. shoulder, rib and loin). Lamb samples were treated at electric field strength of 1–1.4 kV·cm− 1, specific energy of 88–109 kJ·kg− 1, frequency of 90 Hz, pulse width of 20 μs and pulse number of 964. The results showed that prolonged storage time and frozen–thawed pretreatment led to significant increases in volatile compounds due to lipid and protein oxidation. PEF also resulted in significant changes of volatile compounds in different meat cuts. Temporal dominance of sensations (TDS) showed that both storage and PEF treatment affected the temporal flavor of meaty and oxidized flavor attributes. Particularly, longer storage period was associated with oxidized flavor, while PEF treated samples were associated with browned, juicy, livery, and meaty flavor attributes.

Hydrophilic polymer film coat as a micro-container of individual seed facilitates safe storage of tomato seeds

In high-value, low-volume crops like tomato, the high seed multiplication ratio and low seed rate often leads to large quantity of carry over seeds. Seeds lose viability over time, which manifests in poor crop establishment in the field. Hydrophilic polymer seed coating has been examined for better crop establishment and as a delivery system but has not been investigated as a means to maintain seed quality during storage. Hence, the present study was undertaken to investigate the use of hydrophilic polymer (Disco Clear) film coating as a tool for ensuring safe seed storage. Seed moisture kinetics under saturated atmospheric conditions revealed lower moisture adsorption and desorption pattern in hydrophilic polymer-coated seeds as compared to non-coated seeds. However, when exposed to freely available water, hydrophilic polymer facilitated faster and more controlled imbibition, which manifested in reduced mean germination time. Seeds coated with hydrophilic polymer maintained the quality over a longer storage period than non-coated seeds, irrespective of the packaging material and storage conditions. In polymer-coated seeds that were stored in paper bags under ambient room conditions, non-significant differences were observed for all the observed seed quality parameters for longer period thereby indicating its practical application as an alternative to storage under regulated environment. The presence of the hydrophilic polymer film coat acted as a physical barrier for absorption of moisture in the vapour phase and hence, under ambient conditions, the film coated seeds remained effectively protected from equilibration with fluctuating relative humidity, in a manner comparable with storage in moisture impervious containers. Considering this fact, we propose that the polymer film coat in itself acts as a micro-container for seed and thereby facilitates safe seed storage for an extended length of time.

Synthesis of a nanocomposite containing a water-soluble polythiophene derivative and gold nanoparticles

This paper reports on a facile method for synthesizing gold nanoparticles (AuNps) with diameter around 5 nm encapsulated with water-soluble polythiophene sulfonate poly[2-(3-thienyl)ethyloxy-4-butylsulfonate] sodium salt (PTS) and their physical–chemical characterization. The synthesis of hybrid materials of polythiophene derivatives and gold nanoparticles is a way to improve the polymer properties, mainly in application for chemical and optical sensing platforms. The AuNps were prepared by reducing gold salt with acid aqueous sodium citrate by the Turkvich method in the presence of PTS, and both PTS and citrate helped to stabilize the AuNps. The suspensions of AuNp:PTS presented good chemical and photostability for long period of storage. The nanoparticles encapsulated with the polymer presented smaller diameters than those obtained using only sodium citrate, according to scanning electron microscopy images. The AuNps obtained were used for fabrication LbL films with commercial chitosan, which were characterized by impedance spectroscopy measurements. The results showed that the charge transfer resistance values (Rct) decrease as the average diameter of the AuNps decreases and the proportion of PTS increases in the nanocomposite. Such increase of the nanocomposite conductivity, given by the low values of Rct, indicates that the novel film architecture developed is promising for chemical sensing applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1245–1254

쑥부쟁이를 활용한 나물김부각 제조 및 품질특성

Abstract In this study, kim (dried laver) bugak (“KB”), Aster yomena bugak (“SB”), and namul (vegetables)-kim bugak (combination of Aster yomena and kim) (“NB”) were prepared and their quality characteristics were investigated. NB was made by slicing Aster yomena, seasoning it with perilla seeds, attaching it to kim and applying glutinous rice paste, followed by freeze-drying. SB had a higher oil absorption rate than KB, reflecting the high oil absorption rate of namul (here, Aster yomena). DPPH radical scavenging activity was highest for SB; whereas, NB had higher DPPH radical scavenging activity than KB, indicative of the higher antioxidant capacity of namul, as compared to kim. With longer storage period, moisture content tended to be increased, while maximum load, yield stress and hardness tended to be decreased. Overall preference was in the order of NB>KB>SB, without statistical significance. Acid value and peroxide value of NB, stored at 25°C for 40 days, tended to be increased gradually but did not meet the criteria for rancidity. Therefore, NB could be stored at 40 days. Furthermore, it would be possible to make functional bugak using a variety of namul, as well as Aster yomena.Key words: bugak, Aster yomena, namul, quality characteristics, sensory evaluation

146 SPERM STORAGE: EXPRESSION OF PROGESTERONE RECEPTORS, STRUCTURAL PROTEINS, AND HEAT SHOCK PROTEINS IN THE AVIAN OVIDUCT

In avian species, sperm is stored for a long period in sperm storage tubules (SST) located in the utero-vaginal junction. It has been shown that progesterone (P4) regulates the release of sperm from SST for fertilization [Ito et al. 2011 Endocrinology 152, 3952–3621] in quails. In the same context, heat shock proteins (HSP) such as the HSP70 family activate sperm motility in quails [Hiyama et al. 2013 Reproduction 147, 167–178] and may participate in sperm release. In addition, we can hypothesise that at least some structural proteins from SST cells could play a role during sperm storage and release by interacting with sperm. Our objective was to study the potential effect of P4, HSP, and structural proteins on sperm storage potential, by analysing the expression of P4 receptors (PR and mPRα), HSPA8 and HSPB1, CNN1, TAGLN and DES genes in the avian genital tract. Uterus, vagina, and utero-vaginal junctions were collected from 2 divergent lines of hens. One lines displays a long period of sperm storage (21 days, line F+, n = 5), whereas the second displays a shorter period of sperm storage (10 days, line F–, n = 6). Total RNA was extracted and reverse transcribed, and then mRNA coding for PR, mPRα, HSPA8, HSPB1, CNN1, TAGLN and DES were assessed by qPCR (CFX96 Touch Real-Time PCR Detection System, Bio-Rad Laboratories, Hercules, CA, USA). Quantification was performed by using the relative standard curve method. Results were normalized by the geometric mean value of 2 reference genes, GAPDH and S17. Relative amounts of mRNA in each tissue were compared between lines by a Mann-Whitney test. Differences were considered significant when P &lt; 0.05. No significant difference was observed between lines for both P4 receptors, as well as for HSPA8, regardless of the tissue. Expression of CNN1, TAGLN, and DES was significantly higher in the utero-vaginal junction of line F– than line F+ (P &lt; 0.01). Expression of HSPB1 was significantly higher in utero-vaginal junction of line F– than of line F+ (P &lt; 0.05). In conclusion, our data suggest that HSPB1 and structural proteins CNN1, TAGLN, and DES are involved in the regulation of sperm storage in the utero-vaginal junction in hens.

Iron casein succinylate-chitosan coacervate for the liquid oral delivery of iron with bioavailability and stability enhancement.

Iron casein succinylate (ICS) liquid oral preparation as iron supplement has uncomfortable taste after a long period of storage because of its stability, and poor bioavailability of iron compared to any other iron preparations. To improve the chemical stability of ICS and enhance the bioavailability of iron, chitosan-ICS nanoparticles (NPs) were prepared by complex coacervation method and stabilized with polyethylene glycol (PEG) 400. NPs were spherical (mean diameter of 830-1070nm) with positive charge (+30-60mV) depending on the composition of NPs. Addition of PEG400 (2 w/v %) increased the zeta potential (26-50%) and physical stability of chitosan-ICS NPs suspension. Also, NPs decreased iron release compared to ICS after 7-weeks of storage at 4°C. NPs markedly increased the permeability of iron in Caco-2 cell up to 32-38-fold compared to ICS, while physical mixture of chitosan and ICS increased the iron permeability only 2.5-fold. In summary, NPs improved the physicochemical stability and enhanced the transport of iron compared to other iron preparations in Caco-2 cell model. Thus, chitosan-ICS coacervate might be a promising candidate as a liquid oral iron delivery system for iron deficiency patients with stability and bioavailability enhancement.

Short communication: Physicochemical and antioxidant properties of Cheddar-type cheese fortified with Inula britannica extract

Cheddar-type cheese was fortified with the antioxidant Inula britannica flower extract (IBE). Cheddar-type cheeses manufactured with varying concentrations of IBE (0, 0.25, 0.5, 0.75, and 1% wt/vol) were analyzed during storage at 4°C, 0, 1, 2, and 3 wk after production. Higher IBE concentrations resulted in higher protein and ash contents, with a concomitant decrease in pH, total solid, and fat content relative to the unfortified control cheese. The total phenolic content also increased with IBE concentration, but decreased over longer storage periods. The antioxidant activities of the cheeses, determined as 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity and ferric thiocyanate assay results, increased proportionally to the total phenolic content. The highest antioxidant effect was observed in the 1% IBE-fortified cheese, showing 79 and 86% antioxidant effects in the DPPH and ferric thiocyanate assays, respectively. At the 1-wk time point, the 5 cheese preparations underwent sensory evaluation for odor, taste, texture, color, and overall quality, determined using a descriptive analysis by a trained panel (n=20). The addition of IBE resulted in some increases in extract odor and taste. Overall, IBE showed good potential as an antioxidant supplement for dairy products.

GlutaMAX prolongs the shelf life of the culture medium for porcine parthenotes

In vitro porcine embryo production systems have been established and well characterized. However, the efficiency of embryo development during IVC is still very low. In the present study, we have investigated the development of parthenogenetic porcine embryos in the well-known PZM-5 medium for porcine embryos, which was modified by replacing glutamine with the GlutaMAX supplement. We revealed that blastocyst apoptosis was significantly lower in the presence of GlutaMAX, which reduced the release of mitochondrial cytochrome c. Furthermore, the expression of apoptosis genes was significantly lower during GlutaMAX treatment (P < 0.05). The modified medium was also examined for the eventual loss of its efficacy in the presence of GlutaMAX. Three, 6, and 12 months after medium preparation, blastocyst formation in the GlutaMAX-supplemented medium was significantly higher than the number of blastocysts in the medium containing glutamine. After a long period of storage, ammonia concentration was significantly increased in the glutamine medium, whereas it was not statistically different in the GlutaMAX medium. Elevated ammonia concentrations reduced the mitochondrial membrane potential and ATP content of blastocysts in the glutamine medium. These results demonstrate that GlutaMAX can reduce blastocyst apoptosis via inhibition of the cytochrome c pathway and significantly extend the shelf life of the culture medium to at least 1 year.

Changes in Physicochemical Properties of Pork Patty with Dandelion Extract during Refrigerated Storage

This study was carried out to investigate the effects of dandelion leaf, root and whole part extracts on the physicochemical characteristics of pork patties stored at for 10 days. Four types of pork patties were evaluated: ice-water-added (T0), dandelion leaf extract (T1), dandelion root extract (T2) and dandelion whole part extract (T3). The pH decreased significantly during storage, but increased after 10 days of storage. The pH was highest in T0 during storage. The L value of T0 increased whereas T1, T2 and T3 did not significantly changed during storage. The a value decreased with a longer storage period, and the a values for T1, T2 and T3 were higher than that of T0 during storage. The b value did not change significantly during storage. The TBARS increased with a longer storage period, and the values for T0, T1, T2 and T3 were 0.87, 0.29, 0.47 and 0.31 mg MA/kg, respectively, after 10 days of storage. The VBN content value of T0 increased, but those of T1, T2 and T3 did not significantly change during storage. The water holding capacity of T0 decreased, but those of T1, T2 and T3 did not significantly change during storage. Cooking loss increased during storage and that of T0 was higher than those of T1, T2 and T3. Hardness and chewiness decreased while springiness and cohesiveness increased during storage.

Bordonein-L, a new L-amino acid oxidase from Crotalus durissus terrificus snake venom: isolation, preliminary characterization and enzyme stability.

BackgroundCrotalus durissus terrificus venom (CdtV) is one of the most studied snake venoms in Brazil. Despite presenting several well known proteins, its L-amino acid oxidase (LAAO) has not been studied previously. This study aimed to isolate, characterize and evaluate the enzyme stability of bordonein-L, an LAAO from CdtV.MethodsThe enzyme was isolated through cation exchange, gel filtration and affinity chromatography, followed by a reversed-phase fast protein liquid chromatography to confirm its purity. Subsequently, its N-terminal amino acid sequence was determined by Edman degradation. The enzyme activity and stability were evaluated by a microplate colorimetric assay and the molecular mass was estimated by SDS-PAGE using periodic acid-Schiff staining and determined by mass spectrometry.ResultsThe first 39 N-terminal amino acid residues exhibited high identity with other snake venom L-amino acid oxidases. Bordonein-L is a homodimer glycoprotein of approximately 101 kDa evaluated by gel filtration. Its monomer presents around 53 kDa estimated by SDS-PAGE and 58,702 Da determined by MALDI-TOF mass spectrometry. The enzyme exhibited maximum activity at pH 7.0 and lost about 50 % of its activity after five days of storage at 4 °C. Bordonein-L’s activity was higher than the control when stored in 2.8 % mannitol or 8.5 % sucrose.ConclusionsThis research is pioneering in its isolation, characterization and enzyme stability evaluation of an LAAO from CdtV, denominated bordonein-L. These results are important because they increase the knowledge about stabilization of LAAOs, aiming to increase their shelf life. Since the maintenance of enzymatic activity after long periods of storage is essential to enable their biotechnological use as well as their functional studies.

Influence of cold storage prior to and after ripening on quality factors and sensory attributes of ‘Hass’ avocados

Partially-ripened avocados are often held in cold storage in an attempt to enable the consistent delivery of ripe fruit to food service or retail outlets. It is also common to hold fruit without any prior ripening for a few days to several weeks prior to ethylene treatment and final ripening. The purpose of this study was to determine the impact of these practices on ripening time and subsequent fruit quality. ‘Hass’ avocados were harvested from three different orchards on six harvest dates and placed at either 5°C or 12°C immediately after harvest or after ripening to average firmness values of either 80N (partially ripe) or 19N (near ripe). After storage the fruit were then ripened to eating firmness (4.4–6.7N) and evaluated for quality parameters. A portion of the fruit at harvest firmness were stored for 0d, 7d, 14d or 28d and then treated with ethylene to ripen the fruit. Continual softening during storage resulted in fruit that had been ripened prior to storage being nearly at eating firmness at the end of 14d, especially those stored at 12°C. Stem end rot, body rot and pink staining of the vascular tissue occurred more frequently in the previously-ripened fruit after 14d, the severity being greatest at 12°C where the incidence exceeded 50% for both stem end rot and pink staining. Both harvest date and orchard influenced the amount of pink staining observed. Storage of firm fruit prior to ethylene treatment resulted in higher levels of both stem end rot and pink staining only when the storage time exceeded 14d. In an additional study to assess the impact of the storage of partially-ripened fruit on both quality and sensory characteristics, ‘Hass’ avocados were harvested six times at monthly intervals, ripened to approximately 16N firmness at 20°C and then placed at either 1°C or 5°C for 7d or 14d. Following storage the fruit were ripened to eating firmness and evaluated. The occurrence of fruit quality defects was not affected by the timing of ripening. Sensory panelists liked fruit ripened prior to or after cold storage equally well and there were no differences among the ripening treatments, within a storage time, in the level of rich, nutty or grassy attributes that composed the fruit flavor. There were statistically-significant differences in the degree of textural creaminess among the ripening treatments, although these differences were inconsistent and slight. Storing partially ripe ‘Hass’ avocados for up to 4d at either 1°C, 5°C or 12°C does not greatly alter avocado quality, while storage for longer periods, such as 14d, may be problematic due to enhanced development of decay and pink staining, especially at higher temperatures. Holding unripe avocados for longer than 14d prior to ethylene treatment may predispose the fruit to the development of pink staining.

Purification and characterization of two bacteriocins from Lactobacillus brevis BK11 and Enterococcus faecalis BK61 showing anti-Helicobacter pylori activity

The aim of this study was to investigate the antimicrobial effects of purified bacteriocins isolated from Lactobacillus brevis BK11 and Enterococcus faecalis BK61 on Helicobacter pylori. After the final purification step, the molecular weights of the purified bacteriocins from L. brevis BK11 and E. faecalis BK61 were estimated to be approximately 6.5 and 4.5 kDa, respectively. Significant decrease in the antimicrobial activity of these bacteriocins was observed when they were treated with several proteolytic enzymes. However, their antimicrobial activity was stable over long periods of storage and a wide range of pH and was relatively heat resistant. The inhibitory spectrum of the bacteriocin produced by L. brevis BK11 strain was quite narrow, whereas the bacteriocin produced from E. faecalis BK61 strain exhibited a broad antimicrobial spectrum against various foodborne pathogens such as Listeria monocytogenes, Escherichia coli O157, and Salmonella enteritidis. Treatment of H. pylori with these bacteriocins significantly reduced the number of cells of the pathogen found adhering to the monolayers of cultured human gastric adenocarcinoma epithelial cell line (p 0.05).

Improvement in imazalil treatments in commercial packinglines to control green mold on lemon fruit

Long distance to markets limits global competitiveness in lemon fruit production due to fungal postharvest decays, such as green mold caused by Penicillium digitatum. Imazalil, the main fungicide used, is formulated as an emulsifiable concentrate (IEC) and as a water-soluble sulphate salt (IS), the later being less commonly applied in most of the producing countries. The aim of the present report was to improve the effectiveness of imazalil treatments to control green mold in commercial scale. In both laboratory and commercial applications, IS was more effective than IEC. IS formulation applied in water followed by IEC applied in wax is an improved option that provided suitable disease control and optimal residue loading >2.0mgL−1 without exceeding the maximum residue levels. Additionally, IMZ residues remained at acceptable levels after 28 days at 7°C, assuring the protection of lemon fruit for long periods of storage and transports.