Undamaged Kernels Research Articles

Feasibility of impact-acoustic emissions for detection of damaged wheat kernels

A non-destructive, real time device was developed to detect insect damage, sprout damage, and scab damage in kernels of wheat. Kernels are impacted onto a steel plate and the resulting acoustic signal analyzed to detect damage. The acoustic signal was processed using four different methods: modeling of the signal in the time-domain, computing time-domain signal variances and maximums in short-time windows, analysis of the frequency spectrum magnitudes, and analysis of a derivative spectrum. Features were used as inputs to a stepwise discriminant analysis routine, which selected a small subset of features for accurate classification using a neural network. For a network presented with only insect damaged kernels (IDK) with exit holes and undamaged kernels, 87% of the former and 98% of the latter were correctly classified. It was also possible to distinguish undamaged, IDK, sprout-damaged, and scab-damaged kernels.

Effects of processed corn silage on its digestibility and production of growing beef replacement heifers

A study was conducted to determine effects of processing whole crop chopped corn prior to ensiling on diet digestibility and growth of beef replacement heifers. Corn silage (CS) was harvested using two identical six-row self-propelled choppers, one of which was adapted with a roller-processing unit. Corn was chopped to either 13.3 mm (unprocessed; UP) or 10.6 mm (processed; PR) theoretical length of cut (TLC) and ensiled in silage bags. Over the 56-day feedlot study, 90 growing British-cross replacement heifers were randomly assigned to UP or PR CS with three pens per treatment. The diet initially consisted on a dry matter (DM) basis of 55.4% UP or PR CS, 22.3% alfalfa hay (AH), 19.6% wheat middling (WM) and 2.7% supplement (SUPP). Whole plant particle size was estimated from three sub-samples per treatment. Whole cob fraction as a percent of total dry mass was 0.0% for PR and 6.4% for UP ( P<0.05). Undamaged kernels as a percent of the total dry kernel mass were 17.3 for UP and 1.8 for PR ( P<0.05). There was no difference in average daily gain (ADG; 0.96 kg per day versus 1.00 kg per day), DM intake (DMI; 7.55 kg per day versus 7.59 kg per day) or feed to gain ratio (8.12 versus 7.70) between heifers fed UP or PR silages, respectively. Processing of CS did not alter ruminal pH but total VFAs and acetate concentrations were higher in heifers fed the UP treatment ( P=0.04). Treatment had no affect on whole tract DM or acid detergent fiber (ADF) digestibility ( P>0.05) but neutral detergent fiber (NDF) digestibility was higher in heifers fed the PR treatment ( P<0.008). Processing substantially reduced the number of whole kernels in CS and increased NDF digestibility, but did not improve heifer performance on diets containing 55% of DM as CS.

Comparison of the Quality of Hazelnuts Shelled with Modified Conical Sheller and Stone Sheller

Two crackers (a modified conical sheller, widely used in Spain, and a stone sheller, widely used in Turkey) with different sheller characteristics were evaluated in terms of undamaged kernels, damaged kernels, broken kernels, left-in-the-shell kernels, cracked nuts, unbroken nuts and total recyclable nuts. Trials were carried out in a commercial hazelnut processing plant, using the 1996 Akcakoca hazelnut crop, which had a 50% kernel ratio (weight percentage ratio of the kernel to that of the whole hazelnut). The modified conical sheller gave a significantly higher output of undamaged kernels (67·5%) than the stone sheller (61·5%) (P=0·0001). Left-in-the-shell kernels, cracked nuts and total recyclable nuts were significantly lower in the modified conical cracker (about 6, 4·5 and 30%, respectively) compared with those produced by the stone sheller (about 8, 7 and 35%, respectively). The two shellers produced similar levels of damaged kernels (about 3%), broken kernels (about 1%), and unbroken nuts (about 20%). Correlation analysis suggested that a better level of quality (a low percentage of damaged kernels and high percentage of undamaged kernels) can be obtained at the expense of increased unbroken nuts and total recyclable nut percentages for both the modified conical sheller and the stone sheller. At smaller diameter ranges, it is also necessary to accept a higher level of left-in-the-shell kernels for the stone sheller to achieve a better quality of shelled hazelnut.

Effect of Kernel Size, Location, and Type of Damage on Popping Characteristics of Popcorn

ABSTRACTPopping characteristics, specifically expansion volume and popping time, were studied for damaged popcorn. A single variety of commercial undamaged yellow popcorn was separated into four size fractions (D &lt; 4.36, 4.36 &lt; D &lt; 5.16, 5.16 &lt; D &lt; 5.95, and D &gt; 5.95 mm) by screening with round‐hole sieves. Kernels were damaged using a razor knife by either slicing a 2‐mm diameter piece of the endosperm or the germ or by cutting through the pericarp and seed coat into the endosperm or the germ ≈2 mm. A total of five combinations of location and damage were studied (tip cap removed, side cut, side sliced, germ cut, and germ sliced) for each kernel size. A control sample with no damage was also analyzed for each size fraction. All of the damaged kernels (regardless of type of damage) popped, but they had expansion volumes 9.1–47.5% smaller than those of undamaged kernels. The expansion volume of damaged kernels increased by 52.5–85.7%, depending on the damage, when the size of the kernel increased from &lt;4.36 mm to &gt;5.95 mm. Removing the tip cap and slicing through the germ caused less loss of expansion volume than did other types of damage. Damaged popcorn kernels had faster popping times (12.2–24.0 sec) than did undamaged kernels (30.9–34.6 sec). Popping times increased with increasing kernel size for all types of damage.

Foliar Sprays of Bacillus Thuringiensis in Early Corn, 1996

Abstract Sweet corn was planted 2 May in blocks of 4 rows by 25 feet. Each treatment was repeated 4 times in a RCB design. Blocks were separated by 15 feet. Insecticides were applied on 5, 11, and 18 Jul, beginning before tassels emerged. Biweekly treatments were also sprayed on 9, 16, and 22 Jul. ECB flights were monitored with two nylon Heliothis traps baited with a Trece’ pheromone lure (New York or Iowa strain). The CEW flight was monitored with a Heliothis trap with a Hereon Helicoverpa zea lure. Sprays were applied at 75 psi with a four row drop nozzle sprayer pulled (5 nozzles per row) behind a tractor. A hand held applicator delivered 0.5 ml per ear of a 1 ;20 mixture of Dipel ES and food-grade corn oil directly to the silks on 16 Jul. Plots were harvested on 29 Jul. Fifty ears per plot were rated for damage, and for presence of CEW and ECB. Two ratings are reported; Undamaged ears = no feeding on ear; undamaged kernels = no feeding on filled kernels, may have feeding on unfilled tip.

High incidence of Aspergillus flavus and aflatoxins in stored groundnut in Ghana and the use of a microbial assay to assess the inhibitory effects of plant extracts on aflatoxin synthesis.

Groundnut samples from 21 selected markets in the 10 regions of Ghana yielded high levels of the aflatoxigenic fungus Aspergillus flavus on half-strength potato dextrose agar. The fungus was associated with 31.7 and 12.8%, respectively, of all damaged and undamaged kernels assayed. Only 0.24% of total kernels assayed yielded A. parasiticus. Other fungi detected from total kernels assayed were A. niger (34%), A. candidus (1.45%), A. tamarii (3.93%), A. ochraceous (5.26%), Fusarium spp. (1.7%) Penicillium spp. (5.19%), a Mucor sp. (2.3%), a Trichoderma sp. (0.2%), Rhizopus stolonifer (12%) and certain unidentifiable fungi (11.72%). Total aflatoxin levels ranging from 5.7 to 22, 168 ppb were identified with damaged kernel samples. The mycotoxin was not detected in 50% of undamaged kernel samples tested and very low levels mostly ranging from 0.1 to 12.2 ppb were associated with the undamaged samples that tested positive for aflatoxins. In a novel in vitro microbial assay to determine the effectiveness of certain plant extracts against aflatoxin synthesis, extracts from Xylopia aethiopica, Monodera myristica, Cinnamomum verum and Piper nigrum permitted fungal growth in 1.5% potato-dextrose broth while completely suppressing NOR formation. These extracts, however, could not suppress NOR formation in a yeast extract sucrose medium.

Navel Orangeworm (Lepidoptera: Pyralidae) Development in Sunburned Walnuts

Navel orangeworms, Amyelois transitella (Walker), completed development in sunburned walnuts late in the growing season, but moths did not emerge until after harvest. Sunburned walnuts were not attractive to ovipositing moths until considerable hull damage occurred. Only sunburned walnuts with undamaged kernels were suitable for larval development. Navel orangeworm infestation levels up to 38% were recorded in sunburned walnut samples from the San Joaquin Valley, CA. Nut hull tissue damaged by sunburn was not selected over undamaged hull tissue for moth oviposition. Mean kernel temperatures of sunburned walnuts were higher than both undamaged walnuts and ambient air temperature. Premature hullsplit occurred in sunburned walnuts of both early and later maturity varieties. These data suggest that, although sunburned walnuts contribute to the seasonal buildup of navel orangeworms, the late development of navel orangeworms in these nuts reduces the incidence of infestation in hullsplit, new crop nuts.

Neural network parameter effects on object classification and wavelength selection

A back propagative neural network (NN) was used to select visible spectrum (400 to 700 nm) wavelengths and classify damaged and undamaged peanut kernels. Results showed kernel classifications were best, network errors were minimized, and speed of convergence was greatest when the NN was set up with 20 or more hidden nodes, a momentum of 0.45 or less, and using about 1,000,000 learning events. Reflectance data in the 620 to 700-nm range were most influential in classifying kernels followed by relative reflectance in the 400 to 480-nm range. The learning rate did not affect NN performance, but higher learning rates converged more quickly. The most accurate classification performance occurred when the NN had 40 hidden nodes and a momentum of 0.45. These settings resulted in correct classification of 87.8% of all kernels. When compared to statistical means of classifying kernels using data from specific wavelengths or data from a colorimeter, the NN correctly classified about 5% and 13% more kernels, respectively.

Examination of an Aspergillus flavus resistant inbred of maize for cross-resistance to sap beetle vectors

The responses of Carpophilus lugubris and C. freemani (vectors of aflatoxin-producing Aspergillus flavus) and C. hemipterus to milk-stage kernels of 2 A. flavus-resistant cultivars of maize (Mp313E and SC212M) were investigated in the laboratory and in the field in 1990-91. Adults of C. lugubris preferred undamaged SC212M kernels to Mp313E kernels. Kernels from Mp313E that were damaged initially were preferred to undamaged kernels by adults of C. lugubris and adults and larvae of C. hemipterus. Larvae of C. lugubris tended to develop more rapidly on Mp313E than on SC212M kernels. In field tests, C. lugubris damaged fewer kernels of Mp313E than SC212M. It is concluded that undamaged Mp313E kernels may be more resistant to the insects, especially C. lugubris, than SC212M kernels.

Comparison of Yield, Value, and Seed Quality Factors of Florunner and Southern Runner Peanut1

Abstract Florunner and Southern Runner peanut (Arachis hypogaea L.) cultivars were evaluated for yield, market grade and seed infections by Aspergillus spp. following treatment with fungicide programs for control of peanut leaf spot (Cercospora arachidicola Hori and Cercosporidium personatum (Berk. &amp; M. A. Curtis) Deighton) in field trials during 1989 and 1991. The fungicide treatments were: 1) nonsprayed control; 2) chlorothalonil 1.26 kg a.i./ha (seven total applications); 3) the same as treatment no. two except tebuconazole 0.25 kg a.i./ha was substituted for chlorothalonil at applications three and five in 1989; and 4) the same as treatment no. three except cyproconazole 0.23 kg a.i./ha, was used instead of tebuconazole in 1991. Yield, grade ($/m.t.), and total crop value ($/ha) were higher for both cultivars when treated with chlorothalonil and either tebuconazole or cyproconazole than when chlorothalonil was used alone. Southern Runner had significantly lower percent damaged kernels (DK) than Florunner. In addition, Florunner peanuts treated with either tebuconazole or cyproconazole had significantly reduced DK when compared to chlorothalonil alone. Other market grade factors were not significantly different (P&amp;lt;0.05) between cultivars when each was harvested at optimum maturity. Major colonizers of damaged kernels were Aspergillus spp., Fusarium spp., and Rhizoctonia spp. Fungicide treatment and cultivar effects on kernel colonization by Aspergillus flavus Link: Fr. varied between environments. Southern Runner had higher levels of A. flavus contamination in the undamaged kernels than Florunner in 1991, but not in 1989. Possible increased incidence of infection and colonization by A. flavus in Southern Runner require further study.

Ability of Older Cryptolestes ferrugineus (Coleoptera: Cucujidae) Larvae to Infest Whole Corn and Long-Term Population Growth on Whole Corn2

The rusty grain beetle is a cosmopolitan pest of stored products, and may cause grain to spoil and heat. The ability of 2-week-old rusty grain beetle larvae, Cryptolestes ferrugineus (Stephens), to complete development to the adult stage on undamaged corn kernels was compared with development on damaged kernels (undamaged kernels that are slit through the germ with a razor blade) and coarsely cracked corn at 30°C and 75% RH. Both the condition of the corn and infestation level (1 or 5 larvae per cage) significantly affected the proportion of samples in which adults developed. More adults developed in samples containing damaged or coarsely cracked corn than in samples containing undamaged corn. More adults were produced in samples at the higher infestation level. The results indicate that older rusty grain beetle larvae can complete development on sound grain, but more complete development on damaged grain. A long-term test of the ability of rusty grain beetles to infest whole corn was also conducted. Ten adults and ten 2-week-old larvae were placed on 150 g each of: 1) undamaged kernels, 2) damaged kernels, 3) kernels that were sifted to remove dockage but not otherwise selected, and 4) coarsely cracked corn. Population growth at 30°C and 75% RH was monitored over a 36-week period. Population growth on coarsely cracked corn was rapid. This treatment was terminated after 20 weeks, because the corn was deteriorating and population growth was beginning to decline. Final population levels on damaged and unselected corn kernels were high. There was little population growth on undamaged kernels. The results indicate that sound grain is relatively resistant to infestation by rusty grain beetles, even when older larvae are present. Although commercial grain is susceptible to infestation, rate of rusty grain beetle population growth is slow compared to that on damaged grain.

Identifying Undamaged and Damaged Peanut Kernels Using Tristimulus Values and Spectral Reflectance

Peanut kernels from grade samples were sorted into damaged and undamaged categories based measurements from four optical sensing methods. A monochromatic machine vision system, a contact colorimeter, a non-contact colorimeter and a spectrophotometer correctly classified 62.7%, 79.1%, 85.8%, and 94.1%, respectively, of the damaged kernels while correctly classifying 100% of the undamaged kernels. Further analysis of the spectro-photometer data resulted in 99% correct classification of damaged kernels when critical spectral reflectance ranges and line slopes at specific wavelengths were used.

Some factors influencing electrolyte leakage from maize (Zea mays L.) kernels

AbstractEven though the embryo of a maize (Zea mays L.) kernel contributes relatively little to total kernel weight, it is a main source of electrolytes which leach from the kernel during imbibition. Ageing of maize kernels for 18 days at 40°C and a moisture content of about 15% results in an increase of electrolyte leakage which almost exclusively originates from the embryo. The effect of ageing is most apparent after prolonged periods of imbibition. Mechanical damage increases leakage early during imbibition, the effect of damage being considerably larger for aged than for unaged kernels. The large amount of electrolytes measured after the first hour of imbibition of undamaged kernels comes mainly from the pericarp. The electrolyte content of the pericarp is variety dependent and may interfere with quality testing by conductivity measurements.

Rusty Grain Beetle (Coleoptera: Cucujidae) Oviposition in Cracked and Whole Corn2

Number of eggs laid by individual female rusty grain beetles, Cryptolestes ferrugineus (Stephens), during a 72-h period was determined on cracked and whole corn at 75% RH and 30°C. More eggs were laid on finely cracked corn (11.2 eggs/female/72 h) = medium cracked corn (9.6) &amp;gt; coarsely cracked corn (3.9) &amp;gt; whole, slit kernels (1.2) = whole, undamaged kernels (0.4). The results indicate that the greater number of progeny produced on cracked corn, as compared to whole corn, reported in an earlier study must have been, at least partly, due to the greater number of eggs laid on cracked corn.

Effects of Moisture Content and Initial Insect Density on Ability of Rusty Grain Beetles (Coleoptera: Cucujidae) To Infest Whole Corn2

Rusty grain beetle (RGB), Cryptolestes ferrugineus (Stephens), progeny production on undamaged corn kernels (Zea mays L.) and on artificially damaged kernels was investigated at varying moisture contents and initial insect densities. Only three adult progeny were produced on undamaged kernels in both tests. The number of adult progeny produced on damaged kernels increased as moisture content increased from 11.3 to 14.8%, but was still low. Initial insect densities of 1, 2, 5, 10, 20, or 40 RGB on ten kernels of corn did not affect the low number of progeny produced on damaged kernels. These results indicate that even though a high proportion of stored corn contains breaks in the seed coat, growth of RGB populations would be slow if the corn is otherwise intact and is stored at or below 14.8% moisture content.

Weight Compensation of Undamaged Kernels in Response to Damage by Sorghum Midge (Diptera: Cecidomyiidae)

The relationship between level of sorghum midge, Contarinia sorghicola (Coquillett), damage and weight of undamaged kernels, panicle sterility, and kernel weight was investigated in midge resistant and susceptible sorghum, Sorghum bicolor (L.) Moench, hybrid cultivars. A significant inverse relationship existed between the proportion of spikelets destroyed by midges and the weight of undamaged kernels in two of three susceptible hybrids as well as in three of seven case for two resistant hybrids. In only one trial involving a midge resistant hybrid was there a positive correlation between the two variables. However, these relationships were generally not significant at levels of damage below 40%. A significant positive relationship between the percentage of sterile panicle spikelets and of developed kernel weight occurred in half of the cases. Results of this study signify that for midge damage levels near economic threshold levels, the percentage of spikelets damaged by midges was approximately equal to percentage of yield loss—i.e., there was no compensation for midge damage. Partial sterility did not simulate midge damage.

Relationship Between Some Characteristics of the Corn Kernel Pericarp and Resistance to the Rice Weevil (Coleoptera: Curculionidae)1

Two resistant, two intermediate, and two susceptible corn genotypes were used to investigate relationships between physical characteristics of the pericarp and resistance against Sitophilus oryzae (L.). A significantly larger number of eggs were found in kernels without pericarp than in undamaged kernels. No correlation could be found between number of eggs laid and thickness of the pericarp measured in the kernel tip. A paraffin coat applied on the kernel tip, the zone most preferred for oviposition, apparently did not greatly influence the number or location of eggs laid. Pericarp topography did not seem to be associated with resistance. The ovipositional behavior of the females in the treatments used in these experiments may be explained by the presence of an ovipositional stimulant in the corn kernels.

Feeding Damage of Three Stored-Product Moths (Lepidoptera: Pyralidae) on Wheat1

Destruction of kernels of wheat caused by feeding of three species of stored-product moths was studied at 27 to 30 ± 1°C and 80 ± 2% relative humidity. Larvae of Ephestia cautella (Walker) and Plodia interpunctella (Hübner) consumed similar quantities of individual wheat kernels during development. Pyralis farinalis L. consumed significantly more food (P < 0.05) than the other two moths. The part of the kernel eaten, however, varied among the species; P. interpunctella consumed 100% of the bran, P. farinalis 98%, and E. cautella only 40%. No kernels were capable of germinating after 1 week of feeding by E. cautella and P. interpunctella and 2 weeks of feeding by P. farinalis. Unbroken wheat kernels conditioned to 15.2% moisture content were not attacked by any of the three species, but undamaged kernels conditioned to 21.7% moisture content were successfully attacked by some larvae. Larvae of E. cautella feeding on germ and endosperm with or without bran reached the adult stage in 26 to 32 days; P. interpunctella, feeding on the same diet excluding bran, took 12 to 14 days longer than the control to reach the pupal stage.

Feeding and Mortality of Sitophilus granarius (L.) Adults During Simulated Winter Farm Bin Temperatures 1

After gradual cold-temperature acclimation, granary weevils, Sitophilus granarius (L.) (Coleoptera: Curculionidae), fed on cut wheat kernels, but not on undamaged kernels, at 4.4°C. Mortality was greater for weevils confined with single, uncut kernels than for those confined with cut kernels, and males died sooner than females.

Aflatoxin and Mold Flora in North Carolina in 1977 Corn Crop

In a 1977 survey, 187 of 238 maize samples from the Piedmont and Coastal Plain area contained aflatoxin; of these 139 were above the 20 p.p.b. guideline. Aflatoxin G1 was found in 32 samples from the Piedmont/mountain area. The highest level of aflatoxin found was 3622 p.p.b. In general, the higher the percentage of insect-damaged maize the higher the aflatoxin levels found. The sample with the most insect damaged maize (11%) showed a level of 2208 p.p.b., and all samples with 4.5% or more insect damage contained aflatoxin. In general, the greater the infection of maize by Aspergillus flavus the higher the level of aflatoxin, with 7 samples having 40-44 undamaged kernels out of 50 infected. A. niger was found in 10.9% of the samples, but there was no positive correlation with the amounts of aflatoxin found. Strs. of Penicillium funiculosum series isolated from S. Carol. were found again in 25.3% of the total kernels examined. Few other P. or A. spp. were seen. Maize germination was high in most samples. Assuming that most of the aflatoxin G1 was produced by A. parasiticus, a definite ecological correlation was found between G1 and a specific area, i.e. the Piedmont/mountain area.