Master of Science / Department of Grain Science and Industry / Yong Cheng Shi / Octenyl succinic anhydride (OSA) modified starch is widely used in emulsion and encapsulation applications. The functionality of OS starch depends on its molecular structure. A systematic study was performed to investigate the reaction of OSA with granular waxy maize (WM) starch, microporous WM starch and soluble maltodextrin. OS starches were prepared in an aqueous slurry system, and the degree of substitution (DS) of OS starches was determined by titration and [superscript]1H-NMR spectroscopy. For both 3% and 50% OSA treatment, OS maltodextrin had higher DS and reaction efficiency (RE) than OSA modified WM starch and microporous WM starch. The maximum DS of OSA modified granular WM starch was 0.14 and the highest DS of OS maltodextrin was 0.27. For the 3% OSA treatment, the RE for WM starch and maltodextrin was ~ 80% and ~100%, respectively. The structure of OSA modified WM starch and the locations of OS groups on anhydroglucose units (AGUs) were studied by [superscript]1H-NMR and [superscript]13C-NMR. As increasing OS substitution, [superscript]13C - signal at C-1 shifted to upper field. In addition, the [superscript]13C - signal at C-6 shifted to downfield when DS reached 0.073. The results suggested that OS groups were predominantly substituted at the O-2 position and started being substituted at O-6 position when DS was 0.073. FT-IR microspectroscopy was used to detect the heterogeneity OS starch products. Native WM starch, OSA modified WM starches (DS=0.019 and 0.073) and a starch blend with native starch to OSA modified WM starch (DS=0.073) ratio of 7:3 were examined. More than one hundred starch granules of each sample were analyzed one by one by FT-IR microspectroscopy. For the OS starch (DS=0.019), 7% starch granules showed carbonyl absorption. For the OS starch (DS=0.073), 99% starch granules showed carbonyl absorption but the intensity varied, indicating that OSA reacted with most starch granules when DS was 0.073. However, the OS contents of individual granules varied. For the starch blend, only 30% starch granules had carbonyl absorption. FT-IR microspectroscopy is a useful tool to detect heterogeneity of OS starch blends containing native starch.

Master of Science / Department of Grain Science and Industry / Yong Cheng Shi / In vitro digestibility of starch in sorghum grains differing in endosperm hardness and flour particle size was assayed by an Englyst resistant starch (RS) method. The starch digestibility increased as the particle size of flour decreased, but no significant difference in starch digestibility was observed among sorghum flours milled from grains with different hardness. To further understand the digestion of starch in sorghum, the effects of protein on starch digestion and amylose content in starch were determined. pH value was a factor affecting protein digestion since protein digestibility was higher at pH 2.0 than that at pH 1.3. Protein hydrolysis increased with time of pepsin treatment, leading to an increased starch digestion. RS content was 10.61-29.54% in native sorghum flours and 8.47-26.28% in isolated sorghum starch. The amounts of [Gamma]-kafirins extracted increased with time of pepsin treatment while [Alpha]- and [Beta]-kafirins decreased. The starch in sorghum flour with median hardness had a higher amylose content (23.9%) than the starch in hard and soft flours (~21%), which gave lower starch digestibility. Protein digestibility decreased after cooking while starch digestibility increased. Sulfhydryl groups decreased after cooking, indicating that disulfide bonds formed between protein molecules and may have formed a barrier for enzymes to access and digest starch. Confocal laser scanning microscopy (CLSM) showed that the protein matrix was less evident after pepsin treatment. As a result, starch digestion increased after protein matrix was removed.

Master of Science / Food Science Institute / Daniel Y.C. Fung / There are many different environmental sampling methods that are currently used in the industry. They include swab, sponge, flocked swab, direct agar contact, and M-Vac. Several studies have been conducted to determine the benefits and drawbacks of each method. Sampling methods utilized in this study were the swab, flocked swab, and M-Vac. Three surfaces were utilized in this study: ultra high density polypropylene, 304 stainless steel with a 2B finish, and 304 stainless steel with a 2B finish and a buffed surface. Surfaces sampled were 100 cm2. Prior to inoculation, surfaces were autoclaved for 15 min at 121 °C for sterilization. Surfaces were inoculated by either Listeria monocytogenes or Escherichia coli O157:H7 at a concentration of 9 log10 CFU/ml by painting the inoculum onto the surface with a sterilized paintbrush. Brushes were dipped in inoculum for 2 sec before painting from left to right once and then from up to down once. Brushes were redipped for 2 sec and the painting step was repeated. The same brush was used for all E. coli O157:H7 samples and a different brush was used for all L. monocytogenes samples. Then, the surfaces were allowed to dry for 30 min before sampling took place. Listeria monocytogenes samples were appropriately diluted and plated in duplicate onto Tryptic Soy Agar (TSA) and Modified Oxford Media (MOX). Escherichia coli O157:H7 samples were properly diluted and plated in duplicate onto TSA and MacConkey Sorbital Agar (MSA). After plating, dry surfaces were stained using LIVE/DEAD® BacLight™ Bacterial Viability Kit. The Zeiss LSM 5 Pascal confocal laser scanning electron microscope was used for microscopy images and photographs. Six 1 mm by 1 mm random and representative images were taken of each surface. Viable cell count results show that the sponge sampling method, in general, recovered a higher number of microorganisms. The swab was normally shown to recover the least number of microorganisms. When examining the microscopy images it can be concluded that biofilms are more easily formed with L. monocytogenes than E. coli O157:H7. Imaging also allowed for a visual representation of the remaining organisms that made it appear as if there was actually more bacteria recovery when the M-Vac sampling method was employed than when the sponge method was utilized.

Doctor of Philosophy / Department of Grain Science and Industry / Jon M. Faubion / Starch granule surface components were studied as a function of puroindoline haplotype, starch isolation method, and processing fraction. Commonly grown cultivars and near-isogenic wheat lines that varied in their wheat endosperm hardness were collected. Wheat whole-meal, flour and starch were evaluated for their polar lipid composition. Water-washed starch was isolated using a modified batter method and a dough method. Direct infusion tandem mass spectrometry was used to identify the lipid species in the extracts. A total of 155 polar lipid species in wheat meal, flour and starch were quantitatively characterized. The predominant polar lipid classes were digalactosyldiglycerides, monogalactosyldiglycerides, phosphatidylcholine, and lysophosphatidylcholine. Wheat whole-meal, flour and surface-starch contained greater concentrations of total galactolipids while internal-starch lipids contained greater concentrations of monoacyl phospholipids. Wide ranges in starch surface polar lipid concentrations were observed between the two starch isolation methods. Starch isolation methods provided a greater source of variation than did wheat kernel hardness. When dough is optimally mixed the lipids originally on the surface of wheat starch become incorporated into the gluten phase of the dough, whereas in a batter system the starch-surface lipids stay associated with the starch granule surface. The greatest quantities of polar lipids on the starch surface occurred when both puroindoline proteins were present on starch in their wild-type form. Starch surface polar lipid content decreased dramatically when one of the puroindoline proteins was null, or if the puroindoline-b (pin-b) was in the mutated form (Tryptophan-44 to Arginine). Within the hard textured samples, more polar lipids were present on the starch surface when pin-b was in its wild-type form and puroindoline-a (pin-a) was null than when pin-a was in its wild-type form and pin-b was null. The lowest amount of polar lipids were present when pin-b was mutated (Tryptophan-44 to Arginine) and pin-a was in its wild-type form. This indicates the relative importance of pin-b’s presence and structure as it relates to lipid association with the starch granule surface.

Master of Science / Food Science Institute- Animal Science & Industry / Abbey L. Nutsch / This paper reviews the safe production of hard and semi-soft natural cheeses made from pasteurized milk, starter cultures, and enzymatic coagulation. Historically, raw milk has been a source of pathogenic bacteria; however, High Temperature Short Time (HTST) pasteurization has been proven to effectively control these pathogens. The US Public Health Service (USPHS) and US Food and Drug Administration (FDA) promulgate the legal operational parameters in the Pasteurized Milk Ordinance (PMO) and Code of Federal Regulations (CFR) to ensure milk is properly pasteurized and that dairy products are made in accordance with these regulatory standards. A combination of factors in the production of these natural cheeses further inhibits microorganisms. Intrinsic factors include pH, oxidation-reduction potential, water activity, nutrient content, natural inhibitors, and physical integrity. Extrinsic factors include temperature, relative humidity, gaseous environment, cumulative stress, and storage time. These factors contribute to a multiple hurdle effect that inhibits pathogens and spoilage organisms while also providing operational parameters to ensure flavor, texture, and other quality targets. Hard and semi-soft natural cheeses have been associated with few cases of food borne illness over the last few decades. Nevertheless, many operations in the dairy industry have voluntarily implemented food safety systems such as HACCP to ensure the continuous safe production of hard and semi-soft natural cheese.

Master of Science / Food Science Institute / Kelly J. K. Getty / In response to recent claims that synthetic antioxidants have the potential to cause toxicological effects and consumers’ increased interest in purchasing natural products, the meat and poultry industry has been seeking sources of natural antioxidants to replace synthetic antioxidants, which are currently being used by the industry. Due to their high phenolic compound content, fruits and other plant materials provide a good alternative to conventional antioxidants. Plum, grape seed extract, cranberry, pomegranate, bearberry, pine bark extract, rosemary, oregano, other spices, irradiated almond skins, and green tea have functionality as antioxidants in meat and poultry products. Pomegranate, pine bark extract, cinnamon, and cloves have exhibited stronger antioxidant properties than some of the synthetic antioxidants currently used by the meat and poultry industry. Of the discussed natural antioxidants, grape seed extract, cranberry, sage extract, thyme extract, basil extract, ginger extract, pine bark extract, and a Chinese 5-spice blend had the highest percent antioxidant activity (% AOA). (The quality of the antioxidant used may also impact its ability to function as an antioxidant). Some of these natural antioxidants have influenced color and sensory properties of finished meat and poultry products. Plum products used in meat and poultry products have increased redness of the finished product. In some products such as pork sausage or uncured meats, an increase in red color may be desired. Grape seed extract, pine bark extract, rosemary, almond skin powder, some spices and green tea extract have been shown to impact the color of finished meat or poultry products. Plum products and many other spices affect the overall sensory properties of meat or poultry products as well. Depending on the finished product, consumers may view these changes as positive or as negative. When selecting a natural antioxidant to use in a meat or poultry product, the sensory and quality impact on the product should be considered in order to achieve a product with the desired traits.

Doctor of Philosophy / Department of Human Nutrition / Delores H. Chambers / Vegetables are popular among consumers because of their versatility of preparation, unique sensory characteristics, and exceptional health benefits. Trends such as organic farming and breeding to increase nutrition and functional health components have increased interest in understanding the flavor of vegetables, such as leafy greens. A lexicon of thirty-two flavor attributes was created to help describe the flavor of fresh leafy vegetables. This lexicon includes five “green” attributes; mouth feel characteristics such as pungent, bite, tooth-etch, and heat/burn; fundamental tastes including bitter and umami; seven terms that describe unique flavors related to specific vegetables such as cabbage, celery, lettuce, spinach, parsley, beet, and radish leaves; and a group of other terms including citrus, piney, woody, water-like, musty/earthy, floral, sulfur, metallic, soapy, petroleum-like, and overall sweet. In addition, our study encompassed a series of sensory tests which will aid in better understanding the effects of several production variables on the sensory characteristics of pac choi and tomato. Variables evaluated were production systems (i.e. organic and conventional), fertilizer amount (i.e. high, low, and no fertilizer), environment (i.e. field and high tunnel), maturity level (i.e. 2.5, 4.5, and 6.5-week old plants at the time of harvest), and shelf life (i.e. 1, 4, 9, 18 days of refrigerated storage). Samples were grown at the Kansas State University Horticulture Research Center located in Olathe, Kansas. Highly trained descriptive panelists from the Sensory Analysis Center at Kansas State University evaluated the samples. There do not appear to be major sensory differences between organic and conventional products specific to the crops and seasons studied. Furthermore, when differences were present, they generally were quite small and showed no clear trends or patterns favoring one production system over the other even after refrigerated storage. However, it is suggested that differences in flavor and volatile composition between organic and conventional pac choi may be more evident at early stages of growth.

Master of Science / Department of Grain Science and Industry / David L. Wetzel / Isogenic waxy wheat lines differ from their non waxy (normal) parents in functionality, end use, and chemical (i.e. amylopectin/amylose, lipid) contents. Other investigations of waxy and parent wheats involved the carbohydrate and protein fractions. The goal of this work is to apply chemical images to discriminate between the waxy and parent wheats and define the contribution of contrasting lipid profiles. Recent waxy topics include current interest in plant breeding activity to develop new lines that incorporate desirable traits with advantageous success in baking and milling, and the differences needed in milling techniques for waxy versus normal wheats that may be associated with lipids. From our empirical preliminary success in sorting parent wheat kernels from waxy wheat full null specimens by nearIR chemical imaging it was anticipated that using fundamental vibrational spectra in the mid infrared would provide the chemical basis of discrimination. FT-IR microspectroscopic in situ probing and imaging of kernel frozen sections was applied to genetically pure, well documented isogenic breeding lines. With the use of high spatial resolution, elucidation of fundamental vibrations of mid IR provides chemical manifestation of the genetic expression that differentiates waxy wheats from their parent wheats. Comparison between numerous contiguous pixels, typically 3,000 for each type, establishes a consensus and a mean spectrum with characteristic bands for waxy and parent. Extractions with solvents of differing polarity were employed to aid in lipid extraction in situ and kernel extracted endosperm. Differences between kernel sections of waxy and parent are observed using FT-IR microspectroscopic imaging. However, revealing lipid class contribution to the molecular bands required infrared analysis after selective extraction. Triple mass spectrometry of lipid molecule ions was used for compositional analyses to enhance lipid class profile distinction. A normal and waxy advanced breeding line wheat were also analyzed via the same methods. It was noted that digalactoslydyglyercides are the most abundant lipids in all samples, however the relative lipid profiles of normal wheat versus waxy wheat differ as well as tetraploid versus hexaploid. It is observed that in the endosperm of all parent wheat versus waxy wheat specimens analyzed, all waxy wheat specimens contained higher lipid content. Methods were also applied to partial waxy isogenic cultivars to determine detection limits that correspond to the degree of waxy genetic expression.

Master of Science / Food Science Institute-- Animal Science & Industry / J. Scott Smith / Ammonia leaks in meat chilling/frozen storage or processing facilities are not uncommon. Often the meat products are packaged in polymer films that theoretically protect the product from contamination. Unfortunately, there is almost no data on whether ammonia can permeate packaging films. The objectives of this study were to evaluated meat contaminated by low levels of ammonia under frozen storage conditions (-17 ± 3[degree]C), and further evaluated the permeability of common meat packaging films including: low density polyethylene (LDPE), 3 mil Cryovac (E-2300), and 3 mil vacuum (V-PA/PE) at freezing (-17 ± 3 [degree]C) and room temperatures (21 ± 3 [degree]C). Fresh beef Semitendinosus muscles were fabricated to form 10 x 5 x 2.3 cm steaks. The packaging films were fabricated into 10 x 5 cm pouches and filled with 50 mL deionized water. The meat and the pouches were exposed in a plexiglass enclosure, contained in a freezer, to 50, 100, 250, and 500 ppm ammonia gas (85 mL/min) for exposure times of 6, 12, 24, and 48 hr. The ammonia levels in the meat samples were 34.2 (50 ppm exposure), 51.5 (100 ppm exp.), 81.1 (250 ppm exp.), and 116 ppm (500 ppm exp.), and the pH values ranged from 5.56 to 5.75 (control ranged from 5.31 to 5.43) at 48 hr. At freezing temperatures, ammonia residues remained undetected, and no differences in pH were found in the pouches. At room temperature, all pouches were slightly permeable to ammonia; the levels observed in the pouches were, 7.77 ppm (pH, 8.64) for E-2300, 5.94 ppm (pH, 8.38) for LDPE, and 0.89 ppm (pH, 7.23) for V-PA/PE at 500 ppm exposure for 48 hr (unexposed samples pH ranged from 5.49 to 6.44). The results showed that meat packaging materials have low ammonia permeability and thus protect meat products exposed to ammonia exposure during frozen storage. Moreover, meat content is low even with ammonia exposures as high as 500 ppm for up to 48 hr.

Master of Science / Food Science Institute - Animal Science & Industry / Fadi M. Aramouni, Bean, Scott R. / The biochemical, physical and baking properties of caroubin, the main protein in the carob bean, were characterized. The biochemical properties of caroubin were analyzed using reversed-phase high performance liquid chromatography (RP-HPLC), size exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALS) and micro-fluidics analysis. The physical and baking properties of caroubin were characterized via SE-HPLC, laser scanning confocal microscopy, farinograph mixing, and texture profile analyzer analysis. Using a modified Osborne fractionation method, carob germ flour proteins were found to contain ~32% albumin and globulin and ~68% glutelin with no prolamins detected. When divided into soluble and insoluble protein fractions under non reducing conditions it was found that caroubin contained (~95%) soluble proteins and only (~5%) insoluble proteins. As in wheat, SEC-MALS analysis showed that the insoluble proteins had a greater Mw than the soluble proteins and ranged up to 8x107 Da. These polymeric proteins appeared to play a critical role in protein network formation. Analysis of the physical properties of carob germ protein-maize starch dough showed that the dough’s functionality was dependent on disulfide bonded protein networks, similar to what is found in wheat gluten. When baked into a bread these proteins were shown to have a possible improving affect by decreasing staling in gluten-free breads. This was evident when compared to a gluten-free batter bread, and a wheat bread over a five day period.