Agronomy Faculty

Montevideo, Uruguay

Agronomy Faculty

Montevideo, Uruguay
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Aguayo E.,Technical University of Cartagena | Martinez-Sanchez A.,Technical University of Cartagena | Silveira A.C.,Agronomy Faculty | Tarazona M.P.,Jorge Tadeo Lozano University, Bogotá
Acta Horticulturae | Year: 2017

Watermelon juice has gained increasing popularity among consumers as a rich natural source of functional compounds such as lycopene and L-citrulline. This amino acid is an excellent candidate to reduce muscle soreness. Watermelon juice enriched with L-citrulline is presented as an industry opportunity for the sport drink sector. However, the application of conventional thermal pasteurization can degrade those functional compounds. Effects of pasteurization at 80°C for 40 s (PW-40 s) or 90 s (PW-90 s) and storage (4°C for 30 days) on watermelon juice enriched with Lcitrulline was studied. Before pasteurization, initial lycopene content was 14.65±0.30 mg kg-1, reducing to 10.50±0.06 in PW-40 s and 10.10±0.08 mg kg-1 in PW-90 s after 30 days. Initial enriched L-citrulline content was 15.68±0.05 g L-1 that decreased to 12.38±0.03 in PW-40 s and 12.04±0.09 g kg-1 in PW-90 s treatment after 30 days of storage. Pathogenic bacteria (Salmonella spp., Listeria monocytogenes and Escherichia coli) were not detected during storage. However, mesophilic growth was high, reaching 7.5 log cfu mL-1 in PW-40 s and 6.5 log cfu mL-1 in PW-90 s. The appearance limited the shelf life to 25 days for PW-40 s and only 15 days for PW-90 s. The use of higher temperatures of pasteurization is necessary to obtain a safe watermelon juice, but this needs to be balanced with reduced treatment times to maintain functional and sensory parameters which are easily thermo-degraded.

Meikle A.,Laboratory of Nuclear Techniques | Mattiauda D.A.,Agronomy Faculty | Chilibroste P.,Agronomy Faculty
Animal Feed Science and Technology | Year: 2013

The effect of different sward herbage allowances and a total mixed ration (TMR) management on milk production, body condition, first postpartum ovulation and endocrine/metabolic parameters were investigated. Primiparous Holstein dairy cows ( n=44) were randomly assigned to one of the following grazing treatments ( n=11 each): high (HA, 30. kg), medium (MA, 15. kg) and low (LA, 7.5. kg) estimated grass DM available/cow/d and a TMR group fed ad-lib from calving to 56 days after calving. Body condition score (BCS) was registered every 15 days from one month before to two months after calving. Non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), cholesterol, plasma protein, albumin, urea, insulin, insulin like growth factor-I (IGF-I) and leptin were determined in plasma every 15 days from 15 days before to 56 days after calving. Progesterone was determined 2 times per week after parturition to determine first ovulation. TMR group had higher milk production in the first 56 days in milk than the HA and MA groups (P<0.05) which did not differ, and were in turn greater than LA cows (P<0.01). Overall, the TMR and HA groups had a greater BCS, protein and albumin concentrations than the other groups, suggesting a better energy balance. While HA cows presented a better metabolic status (smaller BCS losses, lower plasma NEFA and greater urea concentrations) than MA cows during the early postpartum period (15-30 days postpartum, dpp, P<0.05), HA cows differed (greater plasma cholesterol, albumin and urea concentrations) from LA cows later on (45-60. dpp, P<0.05). Greater plasma insulin and IGF-I concentrations were found in the TMR group (P<0.05), which is consistent with the higher nutrient density offered to this group. The reinitiation of ovarian cyclicity was delayed in MA cows one month after calving when compared to TMR and HA cows (P<0.05), which is consistent with the greater NEFA and lower urea concentrations in this period. The lowest probability of first ovulation throughout the study was observed in LA cows (P<0.05), which was associated with their endocrine and metabolic profile. In conclusion, sward allowance affects metabolic signals which in turn are associated with a different productive and reproductive performance. © 2013 Elsevier B.V.

Aguayo E.,Technical University of Cartagena | Aguayo E.,Institute of Plant Biotechnology | Gomez E.,Technical University of Cartagena | Artes F.,Technical University of Cartagena | And 3 more authors.
Acta Horticulturae | Year: 2013

Fresh-cut watermelon is a relatively new product in Spain, with great consumer appeal. However, even under cold storage, deterioration occurs as juice leakage, loss of texture, colour, and sweetness, reducing the shelf-life of this commodity. The use of calcium chloride (CaCl2) dips using hot water helped to keep the quality of fresh-cut fruits. Cubes of watermelon were dipped into 1 or 0.5% CaCl2 for 2 min at 5 (CWD) or 45°C (HWD). As control, non-dipped watermelon cubes were used. After treatment, fresh-cut watermelon was packaged under modified atmosphere packaging up to 8 days at 5°C. As conclusion the use of 1% of CaCl2 applied in HWD or CWD helped to reduce the levels of CO2 and provided a better final overall quality. HWD, combined with 0.5 or 1% of CaCl2, provided regular and lower levels of respiration rate, helping maintain firmness and the yeast growth. The combination of 1% CaCl2 in HWD provided the lowest psychrotrophic load and was a very effective treatment to maintain quality during 8 days storage at 5°C.

Silveira A.C.,Agronomy Faculty | Aguayo E.,Technical University of Cartagena | Escalona V.H.,University of Chile | Artes F.,Technical University of Cartagena
Innovative Food Science and Emerging Technologies | Year: 2011

The aim of the present study was to investigate if the use of hot water immersion dipping (HWD) alone or combined with other ecofriendly methods, could replace the use of chlorine in fresh-cut fruits such as melon. Melon pieces were subjected to hot (60 °C) or cold (5 °C) water dipping (60, 90, 120 s or 60 s, respectively) followed by immersion in 80 mg L - 1 peracetic acid (PAA) for 60 s at 5 °C or in water, packed in polypropylene trays under passive modified atmosphere (7.4 kPa O 2 and 7.4 kPa CO 2 at steady state), and stored up to 10 days at 5 °C. Respiration rate, ethylene emission, microbial load, flesh firmness, polyamine content and sensorial quality were determined. As main conclusions the longer HWD treatment times (90 and 120 s) followed by PAA dip, provided the lowest metabolic activity and helped to control microbial load without affecting the sensorial quality. In addition, both treatments increased the polyamine content helping to maintain the cell membranes integrity. Industrial relevance: Maintaining quality and microbial safety are the most important concerns of the fresh-cut fruit and vegetables industry. The present study focused on assessing the effect of HWD treatments alone or in combination with PAA, on the respiration rate, ethylene emission, microbial load, flesh firmness, polyamines content and quality retention of fresh-cut Galia melon. According to our results, the use of a heat treatment alone or combined with PAA could replace the use of chlorine, and could be a feasible alternative for fresh-cut industry as a sanitizing method, as or more effective as chlorine. © 2011 Elsevier Ltd. All rights reserved.

Silveira A.C.,Agronomy Faculty | Aguayo E.,Technical University of Cartagena | Artes F.,Technical University of Cartagena
Journal of the Science of Food and Agriculture | Year: 2013

BACKGROUND: Melons (Cucumis melo L.) are widely cultivated in Mediterranean countries. For fresh-cut melon elaboration, factors such as type of cultivar and cut have a significant impact on final product quality. The quality parameters from long, medium and short shelf-life Galia melon cultivars, cut into different shapes such as slices, trapezoids and cylinders and stored up to 10 days at 5 °C, were evaluated in order to learn the suitability of these cultivars and type of cut for minimal processing. RESULTS: In general, long-life melon cultivar had a low respiration rate and ethylene emissions, and high tissue firmness, but low levels of glucose, fructose, vitamin C and flavor rating by consumers. However, despite having higher metabolic activity and susceptibility to microbial spoilage, the short shelf-life cultivar melon had higher firmness retention. This cultivar was characterized by its richness in glucose, fructose and vitamin C, and its sensory quality (flavor) was highly valued. In general, the medium cultivar had an intermediate behavior between long and short cultivars but without their positive attributes. As a consequence of the most intense damage, the cylindrical shape had higher metabolic activity, susceptibility to microbial spoilage and reduced appearance. CONCLUSIONS: In the long and medium-life cultivars studied, low flavor was the limiting factor to extend the shelf-life of fresh-cut melon while for the short-life cultivar the limiting factor was its susceptibility to bacterial growth. Cut types such as cylinders should be avoided. © 2013 Society of Chemical Industry.

Silveira A.C.,Agronomy Faculty | Aguayo E.,Technical University of Cartagena | Artes F.,Technical University of Cartagena
Food Control | Year: 2010

This study evaluated how traditional or new sanitizers, alone, or in combination with the use of a Clean Room (CR), affected the respiration rate, microbial, nutritional and sensorial quality of fresh-cut 'Galia' melon. Melon pieces were packed in polypropylene trays under passive modified atmosphere (7.4 kPa O2 + 7.4 kPa CO2) and stored up to 10 days at 5 °C. The following treatments were performed: 150 mg/l chlorine (control) for 1 min; 80 mg/l peracetic acid (PAA) for 1 min; ozonated water (0.4 mg/l) for 3 and 5 min. The combinations of: ozonated water and PAA; 150 mg/l chlorine and packaging in CR; ozonated water for 3 min and package in CR; ozonated water for 3 min + PAA and packaging in CR were also studied. Throughout the shelf-life psychrotrophic, mesophilic, Enterobactericeae, lactic acid bacteria, moulds and yeast growth were determined. The use of PAA provided the lowest microbial load, but this sanitizer decreased the total vitamin C and the antioxidant activity. Nevertheless, the combination of PAA with 0.4 mg/l of ozonated water (3 min) could be a good substitute of use of chlorine. This treatment was effective in reducing the microbial counts, maintaining the antioxidant compounds and respiration rate and maintained the sensorial quality of the product during the 10 days at 5 °C. Treated product packaged in a CR did not show increased treatment effect, probably due to air quality in the laboratory. The use of CR just for the packaging of the melon pieces did not offer any additional advantage. However, the utilization of CR in an industrial environment during all processing steps (from washing to packaging) should be investigated for potential benefits. © 2009 Elsevier Ltd. All rights reserved.

Silveira A.C.,Agronomy Faculty | Moreira G.C.,Sudan University of Science and Technology | Artes F.,Technical University of Cartagena | Aguayo E.,Technical University of Cartagena
Scientia Horticulturae | Year: 2015

The effect of natural antimicrobials such as vanillin (1 or 2g/L) or cinnamic acid (0.15 and 0.3gL-1) in an aqueous solution or the use of cinnamic vapors through a filter paper placed inside a container (active modified atmosphere packaging-MAP), on the quality of fresh-cut melon stored 10 days at 5°C was assayed. Immersion in water was used as the control treatment. All of these antimicrobial treatments had a good antimicrobial effect, mainly against the mesophilic bacteria (1.5logcfug-1), causing a reduction of Enterobactericeae (2.2logcfug-1). Total polyphenol contents (166mgkg-1 f.w.) decreased with time of storage although fresh-cut melon treated with vanillin (2g/L) and all cinnamon treatments had the highest polyphenol levels with a lower reduction with time of storage. All cinnamon treatments had a lower respiration rate and allowed for better vitamin C retention of melon pieces. The flavor of antimicrobial-treated melon was accepted by consumers, but a vanilla flavor was tasted in melon treated with this compound, although it did not lead to a rejection. A relationship between antimicrobial concentration and microbial population reduction was not found and from this point of view; the use of lower antimicrobial concentrations can be recommended. These natural antimicrobials had good antimicrobial effects and they can be an attractive green alternative for use as sanitizers. The use of cinnamon within active MAP can be helpful in the design of treatments in the packaging industry for fresh-cut products, creating a new opportunity to ensure a safe product. © 2015 Elsevier B.V.

Silveira A.C.,Agronomy Faculty | Aguayo E.,Technical University of Cartagena | Chisari M.,University of Catania | Artes F.,Technical University of Cartagena
Postharvest Biology and Technology | Year: 2011

'Galia' melon is one of the most common cv produced in Spain destined for fresh consumption and/or for the fresh-cut processing industry. Nevertheless, fresh-cut melon is very susceptible to softening during storage, even under chilling and modified atmosphere packaging. This softening process is related to Ca levels in fruit tissue. After preparing trapezoidal shaped sections of 'Galia' melons, the pieces were dipped for 1min a 60°C in Ca chloride, citrate, lactate, ascorbate, tartrate, silicate, propionate or acetate using a Ca concentration equivalent to 0.4% (0.15gg-1) pure Ca chloride, combined with 50mgL-1 H2O2 for controlling microbial growth. Dipping in sterile distilled water (without Ca salt) at 60°C for 1min was used as a control treatment. Firmness, pectin methylesterase and polygalacturonase activity, Ca content, microbial growth, respiration rate, and sensory evaluation, were evaluated throughout 10 days of storage at 5°C under a passive modified atmosphere reaching 4.5kPa O2 and 14.7kPa CO2. At the end of shelf life, Ca ascorbate, chloride and lactate provided melon pieces with a lower respiration rate, increased tissue total Ca content, and maintained a good firmness. In addition, those Ca salts reduced microbial growth. Sensory parameters, such as flavor perception, were kept above the upper limits for marketability. A considerable loss of flavor was found in all treatments except with Ca chlorine, lactate and ascorbate, the only treatments found acceptable from the consumer point of view. © 2011 Elsevier B.V.

Mattiauda D.A.,Agronomy Faculty | Tamminga S.,Wageningen University | Gibb M.J.,Institute of Grassland And Environmental Research | Soca P.,Agronomy Faculty | And 2 more authors.
Livestock Science | Year: 2013

The objective of this study was to assess the effects of restricting access time to pasture and time of grazing allocation on grazing behaviour, daily dry matter intake (DMI), rumen fermentation, milk production and composition in dairy cows. Twenty-one autumn-calving Holstein cows were assigned to one of the following 3 treatments: providing access to a daily strip of pasture for either 8. h between 07:00 and 15:00. h (T7-15), 4. h between 07:00 and 11:00. h (T7-11), or 4. h between 11:00 and 15:00. h (T11-15). The experimental period consisted of 3 weeks of adaptation and 6 weeks of measurements. Cows were offered a daily herbage allowance of 18. kg DM/cow to ground level, 6.1. kg DM/day of a ground sorghum grain-based supplement and 5.2. kg DM/day of maize silage. Milk yield was greater for cows with 8. h access time to the pasture (25.4 vs. 24.1 for 8 and 4. h access time, respectively). Milk yield was not different between cows that access early (T7-11) or late (T11-15) to the grazing session. Milk protein yield was greater for cows with 8. h access time (0.75. kg/d) vs. 4. h access time treatments (0.72. kg/d). Cows with late access time to grazing in the morning produce more protein (0.74. kg/d) than cows with early access to the pasture (0.70. kg/d). Duration of access had a significant effect on herbage DMI (8.3 vs. 6.6. kg/d, for 8 and 4. h access, respectively), but there was no significant effect of time of grazing allocation. Intakes of concentrate and maize silage DM did not differ between treatments.Pasture depletion rate was significantly slower when cows had access to the pasture for 8. h compared with 4. h (0.04 vs. 0.09. cm/h), but was not affected by allocation time in the 4-h treatments.Cows grazed for significantly longer in treatment T7-11 than T11-15, achieved significantly more biting and non-biting grazing jaw movements. However, because herbage DMI did not differ between treatments T7-11 and T11-15, it appears that cows grazed more efficiency on treatment T11-15.The present study showed that reducing the period of access to pasture from 8 to 4. h decreases DMI and milk production. Cows that started their 4-h grazing session later in the morning (T11-15) produced more protein than cows that started earlier (T7-11), probably as a consequence of a larger bite mass and a tendency for higher intake rate. Rumen pH of cows grazing on treatment T11-15 declined faster than in cows on T7-11, which is in accordance with the higher VFA and ammonia rumen concentrations observed after the grazing session started. © 2012 Elsevier B.V.

Chilibroste P.,Agronomy Faculty | Mattiauda D.A.,Agronomy Faculty | Bentancur O.,Agronomy Faculty | Soca P.,Agronomy Faculty | Meikle A.,Laboratory of Nuclear Techniques
Animal Feed Science and Technology | Year: 2012

Effects of daily herbage allowance (DHA) on milk production and composition, body condition score (BCS) and grazing behavior of primiparous Holstein cows during early lactation were investigated. Cows were blocked by body weight (BW), age and BCS, and randomly assigned within block to one of three grazing treatments (. n=. 11 cows each) being: high (HA, 30. kg DM/cow/d), medium (MA, 15. kg DM/cow/d) and low (LA, 7.5. kg DM/cow/d) DHA. Cows were grazed in 8 consecutive grazing paddocks (GP) of 7. d of occupation each. The experiment was a completely randomized block design and data were analyzed as repeated measurement in time. Milk production was higher in HA and MA groups than in LA (24.3 and 22.7 vs. 19.2. L, P<0.01 respectively). Milk response to extra DHA was 0.43. L of milk/kg DHA between LA and MA treatments, which dropped to 0.19. L of milk/kg between LA and HA treatments. Cows in the HA treatment had higher BCS than cows in MA and LA treatments (3.18 vs. 3.05 and 3.07; P<0.05). Cows on all treatments mobilized BCS during the first 3 weeks after calving but, while HA cows lost ~0.5 points of BCS, LA cows lost 1 point. The probability of a cow grazing at any time increased (P<0.01) as the experiment progressed, being 54.5, 61.3, 66.8 and 68.7. min/100. min for GP 3, 5, 7 and 8, respectively. Probability of grazing increased linearly for cows receiving HA (0.39. min/100. min/d) and MA (0.44. min/100. min/d) treatments at higher rate than cows receiving LA (0.22. min/100. min/d) treatment. A linear effect of days in milk (DIM) on bite rate as well as an interaction of DIM by treatment occurred. At DIM. =. 0, the mean value for bite rate was ~15. bites/min, and the slope relative to DIM was higher for HA and MA cows (0.54 and 0.69. bites/min/d, respectively) than for LA cows (0.29. bites/min/d). The result of the present experiment evidence the major role of DHA on milk production in primiparous dairy cows during early lactation, being more important at lower levels of DHA. The lack of response on milk production to higher levels of DHA might have been related to the low effective grazing time and bite rate exhibited by early lactation grazing primiparous cows. © 2012 Elsevier B.V..

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