The purpose of this research was to determine the knowledge, attitudes, and practices of college students toward soy protein and coronary heart disease. A sixteen-question survey was developed to collect data from 211 randomly chosen undergraduate students. Frequencies were tabulated for each question, and relationships were analyzed using the chi square statistic. It was found that only one-fourth or 25.3% of the students answered 4 or 5 out of 5 knowledge questions correctly. Approximately 40% of the students were aware that eating soy protein may help lower one's cholesterol, and 53.1% were familiar with the term soy protein. Eighty-two percent, 66.8%, and 46.4% of the students, and significantly more females, were concerned with the nutritional content, fat content, and cholesterol content of their food respectively, and 74.4% would change an eating habit if it would benefit their health. Of the 26.5% who had never eaten any soy product, significant differences were found between sexes as to why he/she had never eaten a soy product. The analyzed data showed that race was also a factor as Asian students were significantly more likely to be aware of soy's benefit of reducing cholesterol, to have tried any soy product, and to have chosen eating a regular diet enriched with soy protein if faced with hypercholesterolemia. The family unit, schools, newspapers, and doctors' offices were found to be the primary sources of the student's nutritional information. Also, a student with more knowledge was more likely to be concerned with the fat content of food and was more likely to choose soy products. Results of the survey helped to improve the understanding of factors that affect soy food choices and helped to establish a need for soy nutrition education and soy food promotion among college students in preventing the development of coronary heart disease. / Master of Science

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Orientador : Yong Kun Park / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T01:01:25Z (GMT). No. of bitstreams: 1 Lui_MariaCristinaYoun_M.pdf: 779941 bytes, checksum: aa1237e20c91ff048441111b62275d6b (MD5) Previous issue date: 2004 / Mestrado / Mestre em Ciência de Alimentos

Master of Science / Department of Grain Science and Industry / X. Susan Sun / Soybean protein modified with sodium bisulfite behaves like latex adhesives, with adhesive strength comparable to formaldehyde-based adhesives. β-conglycinin and glycinin are two major protein components of the adhesive system. The objective of this research was to investigate the effect of sodium bisulfite on the physicochemical, morphological, and adhesion properties of glycinin and β-conglycinin in order to better understand the function of glycinin and β-conglycinin in the formation of the soy latex adhesive. Sodium bisulfite broke the disulfide bonds that linked acidic and basic polypeptides of glycinin, and the reducing effect was enhanced with increasing sodium bisulfite concentration. Although cleavage of disulfide bonds was expected to destabilize proteins, the thermal stability of glycinin increased as the sodium bisulfite concentration increased. Sodium bisulfite modified glycinin had higher surface hydrophobicity, which facilitated hydrophobic interations between molecules and aggregation of glycinin. The balance between hydrophobic interactions and electrostatic forces makes glycinin form unique chain-like structures. Adhesive performance of glycinin dropped significantly at lower sodium bisulfite concentration and then increased as sodium bisulfite concentration increased up to 24 g/L. Excess sodium bisulfite was detrimental to adhesive strength and water resistance. High-molecular-weight aggregates were observed in unmodified β-conglycinin, but these aggregates were dissociated by sodium bisulfite treatment. Similar to glycinin, the thermal stability of β-conglycinin was improved by the modification. However, the denaturation enthalpy of β-conglycinin decreased significantly at high level of sodium bisulfite (36 g/L). The turbidity at pH 4.8 also dropped extensively at the concentration of 36 g/L. The contact angle of β-conglycinin reached its minimum at 6 g/L sodium bisulfite on cherry wood and 24 g/L on glass. Morphology study proved that sodium bisulfite modification made the β-conglycinin solution more dispersed. At pH 9.5, water resistance of β-conglycinin was improved to a small extent by 6 g/L sodium bisulfite. At pH 4.8, adhesive performance was enhanced by 3 g/L and 6 g/L sodium bisulfite. High level of sodium bisulfite at 36 g/L reduced the adhesive performance of β-conglycinin drastically.

There is demand for improved security of refrigerated ready-to-eat meats. Antimicrobial edible films and coatings could function as an added barrier against post-processing contamination. Hops and hop extracts are known for their antimicrobial efficacy which is attributed to key antimicrobial components including humulones, lupulones, xanthohumol and various terpenoids. Yet, hop ethanol extract has not been studied as an antimicrobial to incorporate into edible protein films and/or coatings. The overall objective of this research was to evaluate hop ethanol extract as an antimicrobial agent incorporated into edible soy protein isolate (SPI) films and coatings, and the influence on the shelf-life and sensory attributes of bologna. Hop ethanol extract was examined for minimum inhibitory concentration before the extract was incorporated into a 6% SPI solution at 0, 10, and 20% levels to determine antimicrobial efficacy as a cast film and simulated coating via zone of inhibition against Listeria monocytogenes strains ATCC 4644, UKADL and ATCC 49594. The results showed that hop ethanol extract alone was inhibitory of all three strains. Moreover, the hop ethanol extract, when incorporated at 10 and 20% (v/v) into edible soy protein isolate (SPI) films and simulated coatings, exhibited antimicrobial action against all three L. monocytogenes strains. Key antimicrobial components, as mentioned above, were identified in the hop ethanol extract via mass spectrometry. The SPI with 10% incorporated hop ethanol extract (SPI+10%hop) antimicrobial coating was applied to bologna, prepared in lab without L. monocytogenes inhibitors, where it exhibited a significant (P ≤ 0.05) bacteriostatic effect against strain ATCC 4644. The SPI+10% hop coating was then applied to a commercial bologna to examine effects on shelf-life and sensory attributes. Significant differences (P ≤ 0.05) were found in instrumental red and yellow colors, however not in sensory color. There was no significant difference (P > 0.05) found in measured lipid oxidation between the bologna with no coating, SPI coating or SPI+10%hop coating. The incorporation of hop did exhibit a slightly bitter taste. Overall, these findings indicate that the SPI+10%hop antimicrobial coating functioned as an inhibitor of L. monocytogenes while producing minimal effects on shelf-life and sensory attributes of bologna.

Doctor of Philosophy / Department of Grain Science and Industry / Xiuzhi Susan Sun / Soy protein is one of the most promising bio-degradable adhesives, with great potential as alternatives synthetic petroleum based adhesives for wood composite industries. However, its intrinsic drawbacks such as low water resistance, high viscosity, and short shelf life still limit its broad application. In this research, soy protein was further modified and characterized to improve adhesion properties, flow-ability, water resistance, and long shelf life, which could facilitate the industrialization of soy protein based adhesives. In this study, we exploited the in situ sodium bisulfite (NaHSO3) modification on soy protein in soy flour-water extracts, and then the modified soy protein was obtained through acid precipitation. First, different concentrations of NaHSO3 were used to modify soy flour slurry, then glycinin-rich and β-conglycinin-rich fractions were precipitated at pH 5.4 (SP 5.4) and pH 4.5 (SP 4.5), respectively. Unmodified sample SP 5.4 and SP 4.5 showed clay-like properties and viscoelastic properties, respectively; whereas with addition of NaHSO3 in range of 2-8 g/L, both SP 5.4 and SP 4.5 had the viscous cohesive phase with good handability and flow-ability. The overall adhesion performance of SP 4.5 was better than SP 5.4; the wet strength of these two fractions was in the range of 2.5-3.2 MPa compared to 1.6 MPa of control soy protein isolate. Then soy protein with various β-conglycinin/glycinin (7S/11S) ratios were extracted from soy flour slurry and characterized for adhesion properties based on the different solubility of 7S and 11S globulins. Seven glycinin-rich soy protein fractions and six β- conglycinin-rich soy protein fractions were obtained. According to the morphology, viscosity, and particle size results, we proposed that proper protein-protein interaction, hydration capacity (glycinin-rich fractions), and certain 7S/11S ratios (β-conglycinin-rich fractions) in modified soy protein are crucial to continuous protein phase formation. The viscous cohesive samples were stable for up to several months without phase separation at room temperature, with the wet adhesion strength of 2.0-2.8 MPa. The soy protein modified with NaHSO3 showed good compatibility with commercial glues applied on plywood and paper labeling fields. The modified soy protein made some functional groups, carboxylic (-COOH), hydroxyl (-OH) and amino groups (-NH2) available, which cross-linked with hydroxymethyl groups (-CH2-OH) from urea formaldehyde (UF) wood glue. The modified soy protein (MSP) with pH 4.8 also acted as an acidic catalyst for the self-polymerization of UF based resin. The wet adhesion strength of MSP/UF blends (40/60) was 6.4 MPa with 100% wood cohesive failure, as compared to 4.66 MPa of UF. As to the paper labeling application, peel strength of MSP on glass substrate increased rapidly, with curing time much shorter than commercial polyvinyl acetate based adhesives (PVAc). And the MSP/ PVAc blends showed shorter curing time, higher water resistance and lower viscosity than pure PVAc. Chemical modification could also enhance the adhesion strength of MSP. 2-octen-1- ylsuccinic anhydride (OSA) was proved to be grafted on soy protein through reaction between amine, hydroxyl groups of protein and anhydride groups. The oily nature and hydrophobic long alkyl chains of OSA mainly contributed to the significant water resistance improvement of MSP.

Antioxidants are molecules capable of stabilizing and preventing oxidation. Certain peptides, protein hydrolysates, have shown antioxidant capacities, which are obtained once liberated from the native protein structure. Soy protein isolates (SPI) were enzymatically hydrolyzed by pepsin and pancreatin mixtures. The soy protein hydrolysates (SPH) were fractionated with sequential ultrafiltration (UF) and nanofiltration (NF) membrane steps. Heat pre-treatment of SPI at 95 degrees celsius (C) for 5 min prior to enzymatic hydrolysis was investigated for its effect on peptide distribution and antioxidant capacity. SPH were subjected to UF with a 10 kDa molecular weight cut off (MWCO) polysulfone membrane. UF permeate fractions (lower molecular weight than 10 kDa) were fractionated by NF with a thin film composite membrane (2.5 kDa MWCO) at pH 4 and 8. Similar peptide content and antioxidant capacity (α=0.05) were obtained in control and pre-heated SPH when comparing the respective UF and NF permeate and retentate fractions produced. FCR antioxidant capacities of the SPH fractions were significantly lower than their ORAC antioxidant capacities, and the distribution among the UF and NF fractions was generally different. Most UF and NF fractions displayed higher antioxidant capacities when compared to the crude SPI hydrolysates, showing the importance of molecular weight on antioxidant capacity of peptides. The permeate fractions produced by NF at pH 8 displayed the highest antioxidant capacity, expressed in terms of Trolox equivalents (TE) per total solids (TS): 5562 μmol TE/g TS for control SPH, and 5187 μmol TE/g TS for pre-heated SPH. Due to the improvement in antioxidant capacity of peptides by NF at pH 8, the potential for NF as a viable industrial fractionation process was demonstrated. Principal component analysis (PCA) of fluorescence excitation-emission matrix (EEM) data for UF and NF peptide fractions, followed by multi-linear regression analysis, was assessed for its potential to monitor and identify the contributions to ORAC and FCR, two in vitro antioxidant capacity assays, of SPH during membrane fractionation. Two statistically significant principal components (PCs) were obtained for UF and NF peptide fractions. Multi-linear regression models (MLRM) were developed to estimate their fluorescence and PCA-captured ORAC (ORAC-FPCA) and FCR (FCR-FPCA) antioxidant capacities. The ORAC-FPCA and FCR-FPCA antioxidant capacities for NF samples displayed strong, linear relationships at different pH conditions (R-squared>0.99). Such relationships are believed to reflect the individual and relative combined contributions of tryptophan and tyrosine residues present in the SPH fractions to ORAC and FCR antioxidant capacities. Therefore, the proposed method provides a tool for the assessment of fundamental parameters of antioxidant capacities captured by ORAC and FCR assays.

With the aim to enhance the efficiency of utilization of crystalline methionine supplemented in the high plant-protein diet for grouper (Epinephelus coioides), this study used Bacillus subtitlis spore as a probiotic additive in the diet to shorten the absorption time difference between protein-bound amino acid and crystalline methionine. The study was conducted in two parts. In the first part, juvenile groupers were fed for 14 weeks with 5 experimental diets: fish meal diet, high plant-protein diet with/without crystalline methionine, as well as with/without B. subtitlis spore separately. Growth performance, PER, protein digestibility, amino acid digestibility, non-specific immune responses, and free amino acid concentration in both muscle and serum were assessed. The second part was a time-series study on serum free amino acids concentration after a force-feeding experiment. The results showed that crystalline methionine supplementation in the high plant-protein diet effectively improved the growth of E. coioides (P<0.05). However, B. subtitlis spore supplementation did not affect fish growth performance significantly (P>0.05). A delay in the appearance of peak serum amino acid concentration was observed when fishmeal was partially replaced by soy protein. On the other hand, the force-feeding experiment showed that serum essential amino acid (include methionine) concentrations droped drastically after they reached the peak concentrations from being forced-fed with the B. subtilis containing diet. Supplementation of crystalline methionine seemed to ease the drop of serum methionine concentration. Based on these results, it is concluded that addition of B. subtitlis spore in high plant-protein diet for the grouper does not enhance the utilization of crystalline methionine, but supplementation of crystalline methionine significantly improve the growth performance of the grouper.