Einfluss von Erntezeitpunkt und Lagerverfahren auf die Druckstellenempfindlichkeit von Äpfeln

The influence of harvest date and storage method on bruises sensitivity of apples was investigated. The cultivars ‘Braeburn’, ‘Jonagold’ and ‘Golden Delicious’ were harvested at three times in an interval of 10 days. Fruits have been stored at 2°C in normal atmosphere (cold storage) or in film bags (CA-/ULO-storage; CA?=?Controlled Atmosphere, ULO?=?Ultra Low Oxygen) for three months. Monthly fruits were bruised by a penetrometer applying a range of pressures. One day later the appearance of bruises were evaluated. Increasing pressures resulted in bruises of increasing severity. Early harvest led to less severe bruises. No differences were observed in storage conditions, but duration of storage increased bruise sensitivity of ‘Braeburn’. In comparison of the three cultivars ‘Braeburn’ was less sensitive than ‘Jonagold’ and ‘Golden Delicious’.     

Untersuchungen zum Auftreten von Druckstellen an Äpfeln nach der Auslagerung

Zusammenfassung Es wurde untersucht, welche Faktoren die Empfindlichkeit von ?pfeln für Druckstellen unmittelbar nach der CA/ULO-Lagerung (CA = Controlled Atmosphere, ULO = Ultra Low Oxygen) beeinflussen. Früchte der Sorten ‘Golden Delicious’ und ‘Jonagold’ wurden nach der CA/ULO-Lagerung für fünf Tage bei vier verschiedenen Nachlagerungsbedingungen (kühl in und ohne Folienbeutel, warm in und ohne Folienbeutel) aufbewahrt. Direkt nach der Auslagerung, ein Tag und fünf Tage sp?ter wurden die ?pfel mittels zwei Apparaturen unterschiedlichen Belastungen ausgesetzt, um Druckstellen zu erzeugen. Weitere gemessene Parameter waren die Fruchtfleischfestigkeit, der Gelbwert, der Gewichtsverlust, der Zellbruchpunkt und die Schalenbruchfestigkeit. Das Ausma? der Druckstellen nahm mit steigender Belastung der Früchte zu. Die warm gelagerten Früchte zeigten mit zunehmender Zeit der Nachlagerung eine geringere Druckstellenempfindlichkeit. Die kühl gelagerten Früchte der Sorte ‘Golden Delicious’ zeigten eine Zunahme der Druckstellenempfindlichkeit im Verlauf der Nachlagerung, die der Sorte ‘Jonagold’ eine Abnahme oder keine Ver?nderung. Ein Zusammenhang zwischen der Druckstellenempfindlichkeit und der Fruchtfleischfestigkeit, dem Zellbruchpunkt oder der Schalenbruchfestigkeit wurde nicht festgestellt.      

Hybrid Variability and Effect of Growth Location on Corn Fiber Yields and Corn Fiber Oil Composition

The variability in commercial corn hybrids for corn fiber yields, amounts of extractable oil, and levels of individual and total phytosterol components in corn fiber oil was determined. Also, the effect of growth location on fiber yields, fiber oil content, and the levels of individual and total phytosterol compounds was determined. Significant variation was observed in the commercial hybrids for fiber yield (13.2–16.6%) and fiber oil yield (0.9–2.4%). No significant correlation was observed between fiber and oil yields. Significant variations in the commercial corn hybrids were also observed in the individual phytosterol compounds in corn fiber oil: 2.9–9.2% for ferulate phytosterol esters (FPE); 1.9–4.3% for free phytosterols (St); and 6.5–9.5% for phytosterol fatty acyl esters (St:E). Positive correlations were observed among the three phytosterol compounds in the corn fiber oil (R = 0.75 for FPE and St:E; 0.48 for St:E and St; and 0.68 for FPE and St). The effect of location on dependent variables was also significant. The same hybrids grown at different locations showed a variation (range) of 4.0–17.5% for FPE, 4.9–12.2% for St:E, and 1.95–4.45% for St. Relative ranking of hybrids with respect to phytosterol composition was consistent for almost all of the growth locations.     

Effect of Mill Plate Setting and Number of Dynamic Steeping Stages for an Intermittent Milling and Dynamic Steeping (IMDS) Process for Corn

Effect of corn degermination mill parameters (clearance between mill plates and rpm) were assessed on the broken germ and number of whole kernels in mash so as to optimize the cracking procedure for the intermittent milling and dynamic steeping (IMDS) process. The dynamic steep time and number of intermittent milling stages for the IMDS process were also optimized for maximum starch recovery. A comparison was made between the IMDS and the conventional steeping process for fraction yields. A clearance of 0.45–0.48 cm between the plates gave the most optimum processing conditions (minimum broken germ and least amount of whole kernels in mash after cracking). Effect of rpm on germ damage and kernel cracking was not significant when optimum clearance between the degermination plates was maintained. Two stages of intermittent milling with a dynamic steep time of 30 min or higher was recommended because it produced the highest yield of starch and germ. Comparison of the IMDS process with the conventional wet‐milling process showed that starch and gluten yield increased by 1.6 and 4.26%, respectively, in the IMDS process. Germ recovered from the IMDS process was 0.54% lower than that from the conventional steeping process.     

Effects of Selected Harvest Moistures and Frozen Storage Times on Selected Yellow Dent Corn: Wet‐Milling Yields and Starch Pasting Properties

The effects of harvest moistures and frozen storage times on corn wet‐milling yields and the pasting properties of the resulting starch were studied. Pioneer hybrid P‐0916‐XR harvested at three moisture contents (49, 35, and 21% wb) were stored frozen for three days or for five months, followed by wet‐milling. The pasting properties of the resulting starch were evaluated with a Rapid Visco Analyzer. The yields of starch and germ increased by 1.2 and 1.9 percentage points, respectively, when harvest moisture decreased from 49 to 21% wb, whereas the yields of steep water solids, total fiber, and gluten decreased by 2.1, 0.7, and 0.6 percentage points, respectively. The frozen corn had lower coarse fiber yields but higher cellular fiber yields. The starch pasting properties showed that peak and breakdown viscosities decreased by 8% (3,824 ± 36 versus 3,520 ± 38 cP) and 13% (2,336 ± 47 versus 2,029 ± 60 cP), respectively, when harvest moisture decreased from 49 to 21% wb, whereas peak time increased by 5% (6.32 ± 0.06 versus 6.62 ± 0.07 min). The setback and final viscosities of starch from long‐term frozen storage (five months) were 14% (1,574 ± 65 versus 1,828 ± 79 cP) and 8% (3,063 ± 27 versus 3,317 ± 101 cP) lower, respectively, than that from control (unfrozen) corn.     

Reducing Steep Time by Adding Lactic Acid During Countercurrent Steeping of Corn with Different Initial Moisture Contents

Reducing corn steep time by adding lactic acid instead of relying on in situ fermentation was studied. Corn at two initial moisture levels (15 and 20%) was steeped for 18 hr in a countercurrent steep system. The initial SO₂ target concentration in steepwater was 2,000 or 3,000 ppm, while the initial lactic acid concentration in steepwater was 0, 0.28, or 0.55%. Adding lactic acid under all steeping conditions decreased steepwater pH, accelerated SO₂ absorption, and increased the amount of solids released from corn. Adding lactic acid during steeping also increased the first grind slurry density and made germ skimming easier than when no lactic acid was added. Starch yields for the hybrid used in this study under all steep conditions were comparable to those from 24‐hr steeping, except when steeping corn with an initial moisture content of 15% in ≈2,000 ppm of SO₂ alone. For the 20% moisture corn, adding lactic acid to fresh steepwater significantly improved the starch yield at ≈2,000 ppm of SO₂ for 18‐hr steeping. At ≈3,000 ppm of SO₂, adding lactic acid did not increase the starch yield for the hybrid used. The protein content in starch was significantly lower when lactic acid was added. Pasting properties of starch were not affected by adding lactic acid. The hybrid used in this study had an initial moisture content of 20% and could be wet‐milled without affecting starch yield, starch protein content, and pasting properties.     

Near-Infrared Reflectance Correlated to 100-g Wet-Milling Analysis in Maize

An understanding of the genetic control of starch, protein, and oil concentrations in the corn (Zea mays L.) kernel is essential for improvement of grain quality. Because large numbers of progenies are needed for genetic studies, a rapid, accurate, analytical procedure is necessary. As part of a study to identify chromosomal regions associated with starch and protein, a rapid near-infrared reflectance (NIR) method and a more labor-intensive 100-g wet-milling procedure were compared for consistency in ranking families and identifying quantitative trait loci (QTL) using a set of 200 F₂S₁ families from the cross of the 70th generations of the Illinois High Protein (IHP) × Illinois Low Protein (ILP) corn strains. NIR starch and wet-milling starch values were highly correlated (r = 0.80), as were NIR protein and gluten measured by wet-milling (r = 0.72). Chromosomal regions associated with NIR starch and wet-milling starch were generally the same. Fiber concentration was significantly negatively correlated with starch and positively correlated with protein. Chromosome regions with significant associations with starch also had significant associations with fiber. The NIR method is satisfactory for measuring starch and protein in material with a wide range of variability in the early stages of a corn-breeding program.     

Single-Stage Short-Duration Tempering of Corn for Dry-Milling

Pilot-scale dry-milling runs were conducted to study the feasibility of using a short-duration single-stage tempering procedure for the tempering-degerminating system, instead of the 17.8–21.5 hr of conventional three-stage tempering procedures reported in the scientific literature. Using a Beall degerminator No. 0, pilot-scale dry-milling experiments were conducted at 10 tempering levels: 0, 5, 10, 15, 30, 45, 60, 120, 180, and 240 min. Variation in moisture content of through- and tail-stock fractions, degerminator throughput, ratio of tail- to through-stock, yields of different sized grits from tail- and through-stock fractions, and the recovery of germ and pericarp were used to compare tempering periods. A decrease in the milling action was observed for tempering durations >30 min. A tempering period of 15 min gave the highest grit recovery and a 30-min tempering period resulted in the highest germ and pericarp recovery. Based on these results, it was concluded that short tempering periods of 10–30 min as compared to 17.8–21.5 hr could be used for the tempering-degerminator system.     

Economics of Germ Preseparation for Dry-Grind Ethanol Facilities

A detailed economic analysis of a 914 tonnes/day (36,000 bu/day) “Quick Germ” ethanol process was performed. The Quick Germ ethanol process is a combination of a dry-grind and a wet-milling ethanol process. The Quick Germ ethanol process increases the coproduct value in the dry-grind ethanol process by recovering germ before fermentation. Germ is recovered using the conventional wet-milling degermination process. Economic assessment of the Quick Germ process proved profitable. The savings achieved by recovering germ as a coproduct and by increasing the fermentor capacity due to removal of nonfermentables from the corn mash will reduce the manufacturing cost of ethanol by 2.69 ¢/L (10.19 ¢/gal or $0.265/bu) when compared to the conventional dry-grind ethanol process.     

Effect of Maize Tempering on Throughput and Product Yields

Scientifically researched 2‐ and 3‐stage tempering procedures and the commercially practiced 1‐stage procedure were compared for throughput and corn dry‐milling product yields at pilot‐scale (30‐kg lots) operation. The throughput and product yields were influenced by the temper procedure and the tailgate weight distance. For most corn dry‐milling products, yields corresponding to 2‐ or 3‐stage tempering procedures could be equaled or surpassed using the 1‐stage tempering procedure at specific temper durations. In general, yields from the 2‐stage and 3‐stage procedures were comparable to the yields from the 1‐stage procedure at temper durations of 30–40 and 50–60 min, respectively. An increase in the tailgate weight distance improved the product yields for temper durations <30 min but reduced the yields for longer temper durations. An increase in temper duration ≤50 min resulted in a reduction in throughput but an improvement in flaking grit yield. The temper duration and tailgate weight distance could be suitably adjusted for obtaining the desired output.