Effects of spontaneous heating on fiber composition, fiber digestibility, and in situ disappearance kinetics of neutral detergent fiber for alfalfa-orchardgrass hays

During 2006 and 2007, forages from 3 individual hay harvests were utilized to assess the effects of spontaneous heating on concentrations of fiber components, 48-h neutral detergent fiber (NDF) digestibility (NDFD), and in situ disappearance kinetics of NDF for large-round bales of mixed alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.). Over the 3 harvests, 96 large-round bales were made at preset bale diameters of 0.9, 1.2, or 1.5 m, and at moisture concentrations ranging from 9.3 to 46.6%. Internal bale temperatures were monitored daily during an outdoor storage period, reaching maxima (MAX) of 77.2°C and 1,997 heating degree days >30°C (HDD) for one specific combination of bale moisture, bale diameter, and harvest. Concentrations of all fiber components (NDF, acid detergent fiber, hemicellulose, cellulose, and lignin) increased in response to spontaneous heating during storage. Changes in concentrations of NDF during storage (poststorage - prestorage; ΔNDF) were regressed on HDD using a nonlinear regression model (R² = 0.848) that became asymptotic after ΔNDF increased by 8.6 percentage units. Although the specific regression model varied, changes (poststorage - prestorage) in concentrations of acid detergent fiber, cellulose, and lignin also increased in nonlinear relationships with HDD that exhibited relatively high coefficients of determination (R² = 0.710 to 0.885). Fiber digestibility, as determined by NDFD, was largely unaffected by heating characteristics except within bales incurring the most extreme levels of HDD or MAX. In situ assessment of ruminal NDF disappearance kinetics indicated that disappearance rate (K_d) declined by about 40% within the range of heating incurred over these hay harvests. The change in K_d during storage (ΔK_d) was related closely to both HDD and MAX by nonlinear models exhibiting high R² statistics (0.907 and 0.883, respectively). However, there was no regression relationship between changes (poststorage - prestorage) in effective ruminal disappearance of NDF and spontaneous heating, regardless of which heating measure was used as the independent variable. The close regression relationship between ΔK_d and measures of spontaneous heating indicates clearly that ruminal NDF disappearance was altered negatively by some direct or indirect aspect of spontaneous heating. However, it was equally apparent that these effects were offset by an expanding pool of dry matter recovered as potentially degradable NDF.     

Effects of spontaneous heating on forage protein fractions and in situ disappearance kinetics of crude protein for alfalfa-orchardgrass hays packaged in large round bales

During 2006 and 2007, forages from 3 individual hay harvests were used to assess the effects of spontaneous heating on concentrations of crude protein (CP), neutral detergent insoluble CP (NDICP), acid detergent insoluble CP (ADICP), and in situ disappearance kinetics of CP and NDICP for large round bales of mixed alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.). Over the 3 harvests, 96 large round bales were made at preset bale diameters of 0.9, 1.2, or 1.5 m and at moisture concentrations ranging from 9.3 to 46.6%. Internal bale temperatures were monitored daily during an outdoor storage period. The change in concentrations of NDICP (poststorage − prestorage) increased with heating degree days (HDD) >30°C in a relationship best explained with a nonlinear model {Y = 24.9 - [22.7 × (e^{−0.000010 × x × x})]; R² = 0.892} that became asymptotic at +24.9 percentage units of CP, thereby indicating that NDICP increases rapidly within bales that heat spontaneously. When maximum internal bale temperature (MAX) was used as the independent variable, the best regression model was quadratic and the coefficient of determination was still relatively high (R² = 0.716). The change in concentrations of ADICP (poststorage − prestorage; ΔADICP) also increased with HDD and was best fitted to a nonlinear model {Y = 14.9 - [15.7 × (e^{−0.0000019 × x × x})]} with a very high coefficient of determination (R² = 0.934). A similar quartic response was observed for the regression of ΔADICP on MAX (R² = 0.975). Increases in ΔADICP as a result of heating (HDD or MAX) were paralleled by concurrent increases in hemicellulose at relatively low increments of heating, but the inverse relationship was observed as hemicelluloses likely became reactive and concentrations decreased in more severely heated hays. Changes in ruminal disappearance rate of CP were best fitted to cubic models for regressions on both HDD (R² = 0.939) and MAX (R² = 0.876); these changes represented an approximate 50% rate reduction in severely heated hays relative to prestorage controls. Within ranges of heating most commonly encountered under field conditions, changes in rumen-degradable protein decreased in a primarily linear relationship with HDD or MAX. However, the mean change in rumen-degradable protein for the 4 most severely heated hays was only −2.6 percentage units of CP, which represents a minimal reduction from prestorage controls and is far less than the maximum of −7.9 percentage units of CP observed with less-severe heating. Interpretation of these results was complicated by poor recovery of NDICP from our most severely heated hays following machine rinsing of 0-h Dacron bags; theoretically, and by definition, this unrecovered pool of NDICP is assumed to be entirely degradable in the rumen. It remains unclear whether these responses could be corroborated in vivo or by other analytical techniques, or whether the magnitude of HDD or MAX for our most severely heated hays exceeds the reliable limits for estimating RDP via in situ methodology.     

Storage characteristics,nutritive value,energy content,and in vivo digestibility of moist,large rectangular bales of alfalfa-orchardgrass hay treated with a propionic acid-based preservative

Unstable weather, poor drying conditions, and unpredictable rainfall events often place valuable hay crops at risk. Recent research with large round bales composed of alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) has shown that these large-bale packages are particularly sensitive to spontaneous heating and dry matter (DM) losses, as well as other undesirable changes with respect to forage fiber, protein, and energy density. Various formulations of organic acids have been marketed as preservatives, normally for use on hays that are not desiccated adequately in the field to facilitate safe bale storage. Our objectives for this study were to (1) evaluate the efficacy of applying a commercial (buffered) propionic acid-based preservative at 3 rates (0, 0.6, and 1.0% of wet-bale weight) to hays baled at 3 moisture concentrations (19.6, 23.8, and 27.4%) on the subsequent storage characteristics and poststorage nutritive value of alfalfa-orchardgrass forages packaged in large rectangular (285-kg) bales, and then (2) evaluate the in vivo digestibility of these hays in growing lambs. Over a 73-d storage period, the preservative was effective at limiting spontaneous heating in these hays, and a clear effect of application rate was observed for the wettest (27.4%) bales. For drier hays, both acid-application rates (1.0 and 0.6%) yielded comparable reductions in heating degree days >30°C relative to untreated controls. Reductions in spontaneous heating could not be associated with improved recovery of forage DM after storage. In this study, most changes in nutritive value during storage were related to measures of spontaneous heating in simple linear regression relationships; this suggests that the modest advantages in nutritive value resulting from acid treatment were largely associated with perturbations of normal heating patterns during bale storage. Although somewhat erratic, apparent digestibilities of both DM (Y = −0.0080x + 55.6; R² = 0.45) and organic matter (Y = −0.0085x + 55.5; R² = 0.53) evaluated in growing lambs were also directly related to heating degree days in simple linear relationships. Based on these data, applying propionic acid-based preservatives to large rectangular bales is likely to provide good insurance against spontaneous heating during storage, as well as modest benefits with respect to nutritive value and digestibility.     

Effects of a propionic acid-based preservative on storage characteristics, nutritive value, and energy content for alfalfa hays packaged in large round bales

During 2009 and 2010, alfalfa (Medicago sativa L.) hays from 2 cuttings harvested from the same field site were used to evaluate the effects of a propionic acid-based preservative on the storage characteristics and nutritive value of hays stored as large round bales. A total of 87 large round bales (diameter = 1.5m) were included in the study; of these, 45 bales served as controls, whereas 42 were treated with a commercial propionic acid-based preservative at mean application rates of 0.5±0.14 and 0.7±0.19% of bale weight, expressed on a wet (as is) or dry matter basis, respectively. Initial bale moisture concentrations ranged from 10.2 to 40.4%. Internal bale temperatures were monitored daily during an outdoor storage period, and heating characteristics were summarized for each bale as heating degree days (HDD) >30°C. For acid-treated bales, the regression relationship between HDD and initial bale moisture was best fitted to a quadratic model in which the linear term was dropped to improve fit (Y=2.02x(2) - 401; R(2)=0.77); control hays were best fitted to a nonlinear model in which the independent variable was squared [Y=4,112 - (4,549×e(-0.000559x*x)); R(2)=0.77]. Based on these regressions, acid-treated bales accumulated more HDD than control hays when the initial bale moisture was >27.7%; this occurred largely because acid treatment tended to prolong active heating relative to control hays. Linear regressions of recoveries of dry matter on HDD did not differ on the basis of treatment, yielding a common linear relationship of Y=-0.0066x+96.3 (R(2)=0.75). Regressions relating changes (post-storage - pre-storage) in concentrations of several nutritional components (neutral detergent fiber, lignin, ash, crude protein, and total digestible nutrients) with HDD for acid-treated hays typically exhibited more inflection points or were higher-ordered polynomial regressions than those of control hays. These more complex responses probably reflected the perturbation of normal heating patterns following acid treatment; however, overall effects on post-storage nutritive value were relatively limited in scope. The potential to improve nutritive value relative to cost for these large round bales was not especially favorable, and hay producers may find that diligence to achieve adequate field desiccation before baling, or use of oxygen-exclusion methods, such as wrapping in plastic, may be better alternatives for preserving moist hays.     

Effects of spontaneous heating on estimates of total digestible nutrients for alfalfa-orchardgrass hays packaged in large round bales

Large round or large square hay packages are more likely to heat spontaneously during storage than hay packaged in conventional (45 kg) bales, and the effects of this phenomenon on the associated energy estimates for these hays can be severe. Our objectives for this project were to assess the relationship between estimates of total digestible nutrients (TDN) and spontaneous heating and to describe any important differences in energy estimates that may result specifically from 2 methods of estimating truly digestible fiber (TD-Fiber). Using the summative approach to estimate TDN, TD-Fiber can be estimated from inputs of protein-corrected neutral detergent fiber (NDFn) and acid detergent lignin (TD-FiberLIG) or from NDFn and 48-h neutral detergent fiber digestibility (TD-FiberNDFD). Throughout 2006 and 2007, mixed alfalfa (Medicago sativa L.)-orchardgrass (Dactylis glomerata L.) hays from 3 individual harvests were obtained from the same 8.2-ha research site near Stratford, Wisconsin. Both options for estimating TD-Fiber (TD-FiberLIG or TD-FiberNDFD) were then used independently via the summative approach to estimate the total TDN concentrations (TDN-LIG or TDN-NDFD, respectively) within these hays. Estimates of both TDN-LIG and TDN-NDFD then were related to heating degree days >30°C accumulated during storage by various regression techniques. Changes (poststorage - prestorage) in TDN-LIG that occurred during storage (ΔTDN-LIG) were best fitted with a nonlinear decay model in which the independent variable was squared [Y = (11.7 × e^{−0.0000033×x×x}) − 11.6; R² = 0.928]. For changes in TDN-NDFD (ΔTDN-NDFD), a quadratic regression model provided the best fit (Y = 0.0000027x² − 0.010x + 0.4; R² = 0.861). Generally, ΔTDN-LIG estimates were 2.0 to 4.0 percentage units lower than ΔTDN-NDFD estimates when heating exceeded 500 HDD. For regressions on maximum internal bale temperature, both ΔTDN-LIG (Y = −0.38x + 16.3; R² = 0.954) and ΔTDN-NDFD (Y = −0.25x + 10.2; R² = 0.848) were best fitted by linear models with heterogeneous (P < 0.001) slopes and intercepts. In both cases, coefficients of determination were high, suggesting that simple measures of spontaneous heating are excellent predictors of energy losses in heated forages. Regardless of method, reductions in TDN were associated primarily with losses of nonfiber carbohydrate, which is known to occur via oxidation of sugars during spontaneous heating. For heated forages, some discrepancy between TDN-LIG and TDN-NDFD existed because the relationship between NDFD and spontaneous heating was shown previously to be very poor, resulting in minimal changes for estimates of TD-FiberNDFD as a consequence of heating. In contrast, TD-FiberLIG declined in close association with heating, largely because TD-FiberLIG was sensitive to changes in concentrations of both NDFn and acid detergent lignin. Discrepancies between TDN-LIG and TDN-NDFD were exacerbated further when neutral detergent fiber rather than NDFn was used to estimate TD-FiberNDFD. Estimates of TDN declined by as much as 13.0 percentage units within severely heated hays, and this is a serious consequence of spontaneous heating.     

Nutritive value, fermentation characteristics, and in situ disappearance kinetics of ensiled warm-season legumes and bahiagrass

This study determined the nutritive value, ensiling characteristics, and in situ disappearance kinetics of bahiagrass (Paspalum notatum Flügge ‘Tifton 9’), perennial peanut (Arachis glabrata Benth. ‘Florigraze’), annual peanut [Arachis hypogaea (L.) ‘FL MDR 98’], cowpea [Vigna unguiculata (L.) Walp. ‘Iron clay’], and pigeonpea [Cajanus cajan (L.) Millsp. ‘GA-2’]. All forages were harvested at maturity stages that optimized dry matter (DM) yield and nutritive value. After harvest, forages were wilted to 45% DM, and 4 replicate bales of each legume and 8 bales of bahiagrass were wrapped in polyethylene and ensiled for 180 d. After each bale was opened, the forage was thoroughly mixed, and representative subsamples were taken for laboratory analysis and in situ incubation. Wilting and ensiling decreased the rumen-undegradable protein, water-soluble carbohydrate, crude protein (CP), and in vitro true digestibility (IVTD) of bahiagrass, perennial peanut, and cowpea, and increased their neutral detergent fiber (NDF) concentrations. Among haylages, CP concentration was greatest for annual peanut, followed by perennial peanut and cowpea, and least for bahiagrass. In contrast, NDF concentration was greater in bahiagrass than in legumes. Pigeonpea had the greatest NDF concentration among legumes and lowest IVTD of all haylages. All haylages were aerobically stable for at least 84 h, but pH was lower in perennial peanut and cowpea than in pigeonpea. Ammonia-N concentrations tended to be greater in legume haylages than in bahiagrass haylage. Butyrate concentration was greater in annual and perennial peanut than in bahiagrass. Total VFA concentration was greater in annual and perennial peanut and cowpea haylages than in bahiagrass haylage. Undegradable DM fractions were greater and extent of DM degradation was lower in bahiagrass and pigeonpea than in other haylages but lag time and degradation rates did not differ. Annual and perennial peanut and cowpea haylages were as aerobically stable and had greater CP, IVTD, and extent of degradation than did bahiagrass haylage; therefore, they are promising forages for dairy cow diets in the southeastern United States.     

Nutritive value and fermentation characteristics of alfalfa-mixed grass forage wrapped with minimal stretch film layers and stored for different lengths of time

A key aspect of managing baled silages is to quickly achieve and then rigorously maintain anaerobic conditions within the silage mass. The concept of inserting an O₂-limiting barrier (OB) into plastic commercial silage wraps has been evaluated previously, yielding mixed or inconclusive results. Our objective for this study was to maximize the challenge to a commercial polyethylene bale wrap, or the identical wrap containing an OB, by using minimal plastic (4 layers), and then extending storage periods as long as 357 d. Forty-eight 1.2 × 1.2-m large-round bales of alfalfa (Medicago sativa L.) and mixed grass forage (66.3 ± 8.66% alfalfa; DM basis) were made at 2 moisture concentrations [47.5 (ideal) or 36.1% (dry)], wrapped with 4 layers of plastic containing an OB or no OB, and then stored for 99, 243, or 357 d. After storage, yeast counts within the 0.15-m deep surface layer were not affected by treatment (mean = 5.85 log₁₀ cfu/g); mold counts could not be analyzed statistically because 26 bales were nondetectable at a 3.00 log₁₀ cfu/g detection limit, but means among detectable counts were numerically similar for OB (4.74 log₁₀ cfu/g) and no OB (4.77 log₁₀ cfu/g). Fermentation characteristics were most affected by initial bale moisture, resulting in a more acidic final pH for ideal compared with dry bales (5.52 vs. 6.00). This was facilitated by greater concentrations of total fermentation acids (3.80 vs. 1.45% of dry matter), lactic acid (2.24 vs. 0.71% of dry matter), and acetic acid (1.07 vs. 0.64% of dry matter) within ideal compared with dry silages. Plastic wrap type had no effect on final concentrations of any fermentation product. During fermentation and storage, we noted greater change in concentrations of fiber components and whole-plant ash within the 0.15-m deep surface layer than in the bale core, and these changes always differed statistically from 0 (no change) based on pre-ensiled baseline concentrations. Overall, concentrations of water-soluble carbohydrates were reduced (mean = 2.3 percentage units) during fermentation and storage, which resulted (indirectly) in increased concentrations of fiber components and crude protein, as well as an overall energy cost of 2.2 percentage units of total digestible nutrient. It remains unclear under what conditions an OB plastic wrap will consistently benefit the fermentation and preservation of baled silages.     

The Effect of Certain Weaving and Finishing Variables on the Wrinkle-resistance of Wool Worsted Fabrics

An account is given of a series of radio-frequency (r.f.) heating trials on three Jumbo bales consisting of different greasy-wool types (merino pieces, merino fleeces, and crossbred fleeces), carried out in the laboratory with a commercially available r.f. generator. The variation of temperature rise within a bale was determined, and the effects of heating at less than rated power and with an air-gap were examined. A further series of trials was carried out on industrial installations, the results of which were in line with expectations based on the laboratory trials. It is concluded that r.f. heating currently provides a method of rapidly heating jumbo bales, although there will always be a large variation of temperatures within a bale.     

Storage and Feeding Losses of Large Round Bales

Alfalfa was harvested in large round bales or small square bales and storage and feeding losses were determined for different storage methods. Large bales were stored 1) in a barn; 2) outside in single rows and uncovered; 3) outside in two-high stacks and covered; and 4) outside in three-high stacks and covered. These bales were fed to dairy heifers with small square bales for comparison. Dry matter storage losses were 2% for large bales stored inside, 6% for large bales stored outside covered, and 15% for large bales stored outside uncovered. Feeding losses of large bales were 12% for stored inside, 25% for stored outside uncovered, and 13 to 15% for stored outside covered. Total losses for large round bales were 40% (stored outside uncovered), 20% (stored outside covered) and 15% (stored inside). Intake and gains were greatest for small bales (2.35 kg/100 kg body weight and .77 kg/d, respectively) and least for large bales (2.11 kg/100 kg body weight and .54 kg/d) stored outside uncovered.Rain penetrated 10 to 25 cm into uncovered bales stored outside. The resulting weathered hay, about 40% of the original bale dry weight, deteriorated. Heifers rummaged through this unpalatable material, and large feeding losses resulted. Storage and feeding losses of large round bales stored outside are economically important enough to warrant protection of bales.     

6—STAPLE-LENGTH VARIATION IN GREASY WOOL

Estimates are reported for the variance of staple length within bales for each of 33 bales taken from separate sale lots of skirted classed merino wool. These variances range from 0.59 to 2.90 cm², with an average of 1.53 cm². Variances between bales, within sale lots of merino wool, were small and not significant. Within-bale variances for comeback and crossbred fleece ranged from 0.61 to 4.62 cm², with an average of 2.64 cm². The highest variances occurred within lots of broken and pieces, these ranging from 1.83 to 6.33, with an average of 3.44 cm².

Evidence is presented which suggests that the removal of short wool during skirting makes the largest contribution to staple-length uniformity, classing having a secondary effect. Of the variation occurring within a bale, about half is found within fleeces and half between fleeces.     

9—THE VALIDITY OF PRESSURE-CORING FOR ESTIMATION OF THE CONTENT OF BURR MEDIC IN WOOL BALES

Miniature wool bales of about normal packing density (approximately 16 lb/ft³ on a greasy-wool basis) were constructed from burr-free greasy wool with burr added in such a way that the true over-all burr content was known. These were sampled with a range of pressure-coring tools differing in size. Except when small coring tools were used in bales of high burr content, there was no significant difference between the mean burr content of several core samples from a miniature bale and the true over-all value for that bale. It is concluded that the act of pressure-coring does not distort the burr content of a sample and that the sample is therefore suitable for determination of clean-wool content. The between-core variance of burr content decreases as the size of coring tool increases.     

Nutritive value of timothy fertilized with chloride or chloride-containing liquid swine manure

Chloride fertilization of timothy (Phleum pratense L.) decreases forage dietary cation-anion difference to an acceptable value [(<250 mmol_c/kg of dry matter (DM)] for dry dairy cows (Bos taurus). However, high Cl concentrations in forages as a result of fertilization might affect nutritive value. Two experiments were used to evaluate the effects of chloride fertilization on timothy spring growth and summer regrowth by determining concentrations of crude protein and neutral detergent fiber (NDF), in vitro true digestibility of DM (IVTD), and in vitro digestibility of NDF (dNDF). In an inorganic fertilization experiment, forages grown at 4 locations were fertilized with CaCl₂ (0, 80, 160, and 240 kg of Cl/ha per yr) or NH₄Cl (160 kg of Cl/ha per yr) in combination with 2 N application rates (70 and 140 kg of N/ha per yr). The increase in Cl fertilization rate affected forage NDF concentration (+1.4%), IVTD (−0.8%), and dNDF (−1.2%) only at the highest rate of N fertilization, but this effect was not of biological importance. Crude protein concentration was not affected by Cl fertilization. Both Cl fertilizer types had a similar impact on forage nutritive value. In an organic fertilization experiment, forages grown at 2 locations received 1 of 7 experimental treatments [unfertilized control, inorganic fertilizer, raw liquid swine manure (LSM), and liquid fractions of 4 pretreated LSM types (decanted, filtered, anaerobically digested, and flocculated)] that provided, respectively, 0, 60, 41, 44, 44, 36, and 101 kg of Cl/ha per yr. The last 6 fertilizer treatments also provided 140 kg of N/ha per yr. The IVTD, dNDF, and concentration of NDF in timothy forage were not affected by the Cl content of the different LSM types. Nitrogen fertilization increased concentration of forage NDF and decreased IVTD and dNDF, but this effect was not biologically important. In both experiments, soil types and harvests had a negligible effect on forage nutritive value. Organic or inorganic Cl fertilizers applied to decrease timothy dietary cation-anion difference have little or no effect on forage nutritive value.     

Effects of temperature,solid content and pH on the stability of black carrot anthocyanins

Anthocyanin stability of black carrots was studied at various solid contents (11, 30, 45 and 64° Brix) and pHs (4.3 and 6.0) during both heating, at 70–90 °C, and storage at 4–37 °C. Monomeric anthocyanin degradation fitted a first-order reaction model. Degradation of monomeric anthocyanins increased with increasing solid content during heating, while it decreased during storage. For example, at pH 4.3, half-life periods for anthocyanins at 30, 45 and 64° Brix were, respectively, 8.4, 6.9 and 5.2 h during heating at 80 °C and 18.7, 30.8 and 35.9 weeks during storage at 20 °C. At 30–64° Brix, increasing pH from 4.3 to 6.0 enhanced the degradation of anthocyanins during heating. The effect of pH on thermal stability of anthocyanins was also studied at six different pHs (2.5–7.0) in citrate-phosphate buffer solutions and significant decrease in anthocyanin stability was observed at pHs above 5.0. Higher activation energies (E_a) were obtained during heating than during storage with increasing solid contents. At 30–64° Brix, E_a values ranged from 68.8 to 95.1 kJ mol⁻¹ during heating and from 62.1 to 86.2 kJ mol⁻¹ during storage. Q₁₀ values at 20–37 °C were as high as 3.1 at 45° Brix and 3.6 at 64° Brix.     

Effects of light,temperature and water activity on the kinetics of lipoxidation in almond-based products

Lipoxidation in almond-derived products was investigated using the chemiluminescence (CL) and thiobarbituric acid-reactive substances (TBARS) methods to detect the first and later reaction products, respectively. The effects of light during storage at 5 °C, 22 °C and 40 °C were studied, as well as the effects of combined heat/water activity treatments in the 60–120 °C and 0.38–0.72 range. During storage, light was found to enhance the CL and TBARS values, and specific responses were observed in almond paste and the final Calisson product. During the heating of almond paste, as the initial water activity (a_w) increased, the CL rate constants increased during heating to 60 °C and 80 °C, but interestingly, these values decreased during further heating to 120 °C, whereas the maximum TBARS rate constants occurred at a_w 0.57 at all the heating temperatures tested. The activation energies, based on the CL and TBARS values, decreased specifically when the a_w increased from 0.38 to 0.72, giving overall values ranging from110 kJ mol⁻¹ to 60 kJ mol⁻¹. Likewise, in the same water activity range, the temperature-dependent rate constant enhancing factor (Q₁₀) decreased from 3.3 to 1.6.     

Biochemical,sensory and microbiological attributes of wild turbot (Scophthalmus maximus), from the Black Sea,during chilled storage

Freshness of wild turbot (Scophtalmus maximus) stored in ice was assessed by chemical, sensory and microbiological methods. The limit for sensory acceptability of wild turbot stored in ice was ∼12–15 days. The quality of turbot decreased on day 15 (B) and they were no longer acceptable on day 19 (C). The TVB-N level showed fluctuations during storage, indicating that TVB-N could not be a good indicator of turbot quality. The release of FFA increased from an initial value of 6.33 (expressed as % of oleic acid) to a final value of 20.6 during the storage period. The initial PV value was 5.60 meq/kg for turbot stored in ice and it started to increase to 21.6 meq/kg on day 12 and then started to decrease to 13.6 meq/kg at the end of storage period. The level of TMA in wild turbot increased sharply from an initial value of 9.36 mg/kg to a final value of 38.9 mg/kg. Linear regressions (r²) obtained from K, K_i, G, P, H and F_r were 0.92, 0.89, 0.99, 0.89, 0.96 and 0.89, respectively, for the wild turbot stored in ice. Turbot maintained high (E) and good quality (A) during the first 12 days of chilled storage when the average K, K_i and P values were ∼78–85%, and H, F_r and G values were ∼45%, 15% and 149%, respectively. Eight biogenic amines were investigated, namely, histamine, putrescine, cadaverine, spermidine, spermine, tryptamine, tyramine, and 2-phenylethylamine, three amines (histamine, tyramine, and tryptamine) were not detected in any of the fish samples during the storage period. As storage time progressed, putrescine and cadaverine became the dominant amines, reaching 22.7, and 16.9 mg/kg, respectively, at 19 days of storage in ice. Total viable counts of whole gutted turbot increased from the initial value of 3.3 log cfu g⁻¹ (day 0) to 7.87 log cfu g⁻¹ (day 19) over the period of storage. If 10⁶ microorganisms/g are considered to be the TVC limit of acceptability, the shelf life of turbot was approximately ∼13–14 days.     

Effects of freezing rates on starch retrogradation and textural properties of cooked rice during storage

The effects of freezing rates and storage temperatures on starch retrogradation and textural properties of cooked rice were evaluated. Cooked rice was frozen with different freezing rates and then stored at 4 °C for 14 days or −18 °C for up to 7 months. Starch retrogradation enthalpy (ΔH_r) of cooked rice was determined by a differential scanning calorimetry, and textural properties were determined by a texture analyser. The results showed that the ΔH_r and hardness values had a negative correlation with freezing rate, however, a positive correlation was found between adhesiveness and freezing rate. On the other hand, the advantages (lower hardness and higher adhesiveness, less starch retrogradaton) of cooked rice gained by rapid freezing, were lost quickly in the first 3 days of storage at 4 °C. However, rapid freezing combined with −18 °C frozen storage can effectively retard starch retrogradation and maintain the textural properties of cooked rice for at least 7 months. Therefore, high quality cooked rice can be produced by combined rapid freezing with frozen storage.     

Spectroscopic and molecular docking studies of the interactions of sunset yellow and allura red with human serum albumin

Binding interactions of human serum albumin (HSA) with sunset yellow (SY) and allura red (AR), two food colorants, were investigated at the molecular level through fluorescence and UV absorption as well as molecular docking. The collective results of the study under the simulated physiological conditions proposed a static type of binding occurring between the two dyes and HSA. When compared with AR (293 K: Ksv = (4.21 ± 0.36) × 10⁴ L·mol⁻¹; K_b = (0.30 ± 0.23) × 10⁶ L·mol⁻¹), SY (293 K: Ksv = (6.80 ± 0.10) × 10⁴ L·mol⁻¹; K_b = (3.11 ± 2.01) × 10⁶ L·mol⁻¹) had stronger quenching ability and higher affinity for HSA due to less steric hindrance. It can be deduced that the energy transfer from HSA to the two dyes occurred with high probability based on the Förster resonance energy transfer theory (r < 7 nm, 0.5 R₀ < r < 2.0 R₀). The spectral analysis suggested that the formation of the dye-HSA complex resulted in the change in microenvironment around Tyr and Trp residues and in the secondary structure of the protein. According to molecular docking simulation, the two structural analogs almost bound to the same site of HSA, near Sudlow's Site I, but significant difference existed in the number and location of hydrogen bond (H-bond) formed between the dyes and HSA. From the molecular docking along with the thermodynamic parameters (AR: ΔH^o = −(58.79 ± 15.24) kJ·mol⁻¹, ΔS^o = −(115.1 ± 31.10) J·mol⁻¹·K⁻¹; SY: ΔH^o = −(52.24 ± 3.15) kJ·mol⁻¹, ΔS^o = −(50.07 ± 11.14) J·mol⁻¹·K⁻¹), it could be inferred that H-bond and van der Waals forces were the major binding forces involved in formation of the dye-HSA complexes.     

Aerobic stability of wheat and orchardgrass round-bale silages during winter

Using recently developed technology, balage is often stored in large (1.2 x 1.2 m) round bales that are wrapped in plastic film with an in-line wrapper. The aerobic stability of this fermented forage is important, particularly during winter months when it is fed to livestock or sold as a cash crop. Two types of forage, orchardgrass [Dactylis glomerata L.; 54.4% dry matter (DM)] and wheat (Triticum aestivum L.; 62.4% DM), were packaged in large round bales and wrapped with an in-line wrapper during May 2002. Twenty-one bales of each balage type were unwrapped and exposed to air on Dec. 10, 2002 for 0, 2, 4, 8, 16, 24, or 32 d (ambient temperature range = 0.6 to 19.4 degrees C) to evaluate aerobic stability. For both orchardgrass and wheat balage, final bale weight, concentration of DM, and pH were not affected by exposure time. Across both balage types, DM recoveries were > or = 97% for all bales, indicating that both balage types were very stable when exposed to air. For orchardgrass balage, exposure time had no effect on concentrations of NDF, ADF, hemicellulose, cellulose, or lignin, thereby indicating that little deterioration occurred. Similarly, no contrast relating any fiber component with exposure time was significant for wheat balage. Concentrations of crude protein (CP) were not affected by exposure time for wheat balage, but there was a tendency for exposed orchardgrass bales to have greater concentrations of CP than bales sampled on d 0. Exposure time had no effect on 48-h in situ digestibility of DM for wheat balage, but there was a tendency for a linear increase with exposure time for orchardgrass balage. However, the overall range (78.2 to 80.5%) over the 32-d exposure period was very narrow, and this response is probably of limited biological significance. Generally, concentrations of fermentation acids were low, primarily because of the high concentration of DM within these balages, and only minimal changes in these acids were observed over the exposure interval. These results suggest that the balage evaluated in this trial during winter conditions was very stable after exposure to air for up to 32 d. This should allow for considerable flexibility with respect to feeding, transport, and marketing of balage during winter months without significant aerobic deterioration.     

Some properties of corn grains and their flours I: Physicochemical,functional and chapati-making properties of flours

The variability in physical (1000 kernel weight and bulk density) and mechanical (rupture force) properties of grains from different Indian corn varieties (African tall, Ageti, Early composite, Girja, Navjot, Parbhat, Partap, Pb sathi and Vijay) were studied. The functional (colour, gelatinization, retrogradation and pasting) and chapati-making properties of flours milled from corn varieties were evaluated. African tall flour showed the highest enthalpy of gelatinization (ΔH_gel), peak-, trough-, breakdown-, final-, and setback viscosities, and L^∗ (84.4) value and resulted in chapaties with higher extensibility (5.76 mm) and of light colour. African tall flour, with the lowest protein content, showed the lowest grain rupture force. Amylose content and hardness of starch gel from African tall were found to be the lowest among all corn varieties. Girja flour, with the lowest transition temperatures and ΔH_gel, showed the lowest extensibility of chapaties made from it. Pearson correlations between physical and textural properties of corn grains and the functional properties of their flours were established. Rupture force of corn grain and protein content of flour showed a negative correlation with peak viscosity of flour (r = −0.917, and −0.863, p < 0.01). The protein content of flours was negatively correlated with L^∗ (r = −0.759, p < 0.01) value and positively with b^∗ (r = 0.635, p < 0.01) value. Pasting temperature of flours showed a significant negative correlation with peak, trough, breakdown, final and setback viscosities (r = −0.836, −0.846, −0.778, −0.871, and −0.847, respectively, p < 0.01). Pearson correlation was also established between the grain and starch properties. Rupture force of corn grains was positively correlated with the amylose content of starch (r = 0.950, p < 0.01).     

Some properties of corn starches II: Physicochemical,gelatinization, retrogradation,pasting and gel textural properties

The physicochemical, thermal, pasting and gel textural properties of corn starches from different corn varieties (African Tall, Ageti, Early Composite, Girja, Navjot, Parbhat, Partap, Pb Sathi and Vijay) were studied. Amylose content and swelling power of corn starches ranged from 16.9% to 21.3% and 13.7 to 20.7 g/g, respectively. The enthalpy of gelatinization (ΔH_gel) and percentage of retrogradation (%R) for various corn starches ranged from 11.2 to 12.7 J/g and 37.6% to 56.5%, respectively. The range for peak viscosity among different varieties was between 804 and 1252 cP. The hardness of starch gels ranged from 21.5 to 32.3 g. African Tall and Early Composite showed higher swelling power, peak, trough, breakdown, final and setback viscosity, and lower ΔH_gel and range of gelatinization. Pearson correlations among various properties of starches were observed. Gelatinization onset temperature (T_o) was negatively correlated to peak-, breakdown-, final- and setback viscosity (r = −0.809, −0.774, −0.721 and −0.686, respectively, p < 0.01) and positively correlated to pasting temperature (r = 0.657, p < 0.01). ΔH_gel was observed to be positively correlated with T_o, peak gelatinization temperature and (T_p) and gelatinization conclusion temperature T_c (r = 0.900, 0.902 and 0.828, respectively, p < 0.01) whereas, it was negatively correlated to peak- and breakdown- (r = −0.743 and −0.733, respectively, p < 0.01), final- and setback viscosity (r = −0.623 and −0.611, respectively, p < 0.05). Amylose was positively correlated to hardness (r = 0.511, p < 0.05) and gumminess (r = 0.792, p < 0.01) of starch gels.