ABSTRACT Effects of Filtration Temperature and Heat Treatment on Composition and Rheological Properties of Whole Milk Ultrafiltration Retentates John William Montella For the first part of my thesis, the effects of filtration temperature and heat treatment on the compositional properties of whole milk Ultrafiltration retentate (UF) were studied. Ultrafiltration is primarily run at temperatures in the range of 50-55°C but more and more plants are starting to filter at refrigeration temperatures. In the ultrafiltration of milk, filtration temperature can affect the composition of the retentate by affecting the chemistry of milk components. The application of a pasteurization step can also affect the chemistry of milk components. There were two filtration temperatures used: 10°C and 50°C. The effect of stage in the filtration process in which the pasteurization step is applied (before UF vs. after UF) is also studied. The heat treatment used was a batch pasteurization treatment of 63°C for 30 minutes. The milk was concentrated to a Volume Concentration Ratio (VCR) of 3X through a 10,000 Molecular Weight Cut Off polysulfone membrane. Compositional analysis was performed on permeate and retentate. According to my results, there were significant treatment effects on the retention of true protein (both casein and whey protein nitrogen), total protein, non-casein nitrogen, minerals (including Ca) and pH of the retentate. The chemistry of the milk components were considered as possible reasons for these differences. The week of processing did not affect the results. For the second part, the effect of composition of the retentate on their viscosity and flow properties was observed. Rheological properties are very important in process design and for consumer acceptability. Flow and viscosity data was collected using a dynamic stress rheometer. Three analytical temperatures were used during the rheological measurements: 10°C, 40°C, and 70°C. A shear rate of 500 s-1 was used for viscosity analysis. Flow properties were also observed using the same three temperatures. According to the results, all the retentate displayed shear thinning behavior and this behavior became more pronounced as the testing temperature increased. As the shear rate increased, there was a shear thickening effect that became more pronounced as temperature increased. There was a significant effect of treatment on the viscosities of the retentate. Compositional differences in the retentate are possible contributors to observed results. The week of processing had no effect on the results. For the final part, the effect of filtration temperature and heat treatment on rennet coagulation time of retentate was observed. A 22μl aliquot of chymosin was added to 100 ml of retentate heated to 30°C prior to analysis. Rennet coagulation time was monitored using a dynamic stress rheometer. The rennet coagulation time was recorded as the time at which the G’ value reached 1 Pa. There was a significant effect of filtration temperature and heat treatment on the rennet coagulation time of the retentate. Compositional differences are all possible contributors to these differences. From the observations from all three studies, the following conclusions can be made: (1) There were significant differences observed with respect to filtration temperature and heat treatments on chemical composition of the retentate; (2) The retentate displayed a shear thinning behavior and the chemical composition of the retentate could be a contributing factor as well as the sample testing temperature. There was also a significant treatment effect on the viscosity of the retentate; and (3) Significant differences in rennet coagulation times were observed, possibly due to compositional differences of retentate. Processing week did not have a significant effect on my results.

<p>When starch granules are gelatinized, many complex structural changes occur as a result of large quantity of water being absorbed. The enlargement of granule sizes and the leaching out water-soluble macromolecules contribute to the viscoelasticity. Starch pasting behavior greatly influences the texture of a variety of food products such as canned soup, sauces, baby foods, batter mixes etc. It is important to characterize the relationship between the structure, composition and architecture of the starch granules with its pasting behavior in order to arrive at a rational methodology to design modified starch of desirable digestion rate and texture. Five types of starch used in this study were waxy maize starch (WMS), normal maize starch (NMS), waxy rice starch (WRS), normal rice starch (NRS) and STMP cross linked normal maize starch. Evolution of volume fraction φ and pasting of 8% w/w starch suspension when heated at 60, 65, 70, 75, 80, 85 and 90 °C were characterized by particle size distribution and G’, G” in the frequency range of 0.01 to 10 Hz respectively. As expected, granule swelling was more pronounced at higher temperatures. At a fixed temperature, most of the swelling occurred within the first 5 min of heating. The pastes exhibited elastic behavior with G’ being much greater than G”. G’ increased with time for waxy maize and rice starch at all times. G’ and G’’ were found to correlated only to the temperature of pasting and not change much with the rate of heating. For WMS, WRS and STMP crosslinked NMS, G’ approached a limiting value for long heating times (30 min and above) especially at heating temperatures of 85°C and above. This behavior is believed to be due to the predominant effect of swelling at small times. For normal maize and rice starch, however, G’ reached a maximum and decreased at longer times for temperatures above 80 °C due to softening of granules as evidenced by peak force measurements. For each starch sample, the experimental data of G’ at different heating temperatures and times could be collapsed into a single curve. The limiting value of G’ at high volume fraction was related to granule size and granule interfacial energy using a foam rheology model. The interfacial free energy of granules were obtained from contact angle measurements and was employed to evaluate the limiting G’. The experimental data of G’ for all starches when subjected to different heating temperatures and times were normalized with respect to the limiting value at high volume fractions. The master curve for normalized G’ was employed to predict the evolution of G’ with time for different starches which was found to agree well with experimental data of storage modulus. A mechanistic model for starch swelling that is based on Flory Huggins polymer swelling theory was employed to predict the evolution of volume fraction of swollen granules. The model accounts for the structure and composition of different types of starches through starch-solvent interaction as quantified by static light scattering, gelatinization temperature and enthalpy of gelatinization, porosity and its variation with swelling and crosslinking of starch molecules within the granule from equilibrium swelling. Consequently, one could predict the evolution of texture of these starch suspension from the knowledge of their swelling behavior. Expressing the limiting storage modulus of complete swelling (volume fraction approaching unity) of starch suspension in terms of foam rheology, we were able to normalize the storage modulus of different types of starches with respect to its limiting value which is found to fall into a master curve. This master curve when employed along with the swelling model resulted in the successful prediction of development of texture for different types of starches. The above methodology can quantify the effects of structure and composition of starch on its pasting behavior and would therefore provide a rational guideline for modification and processing of starch-based material to obtain desirable texture and rheological properties.</p> <p> </p>

Food allergies are an increasing health problem throughout the developed world. Among these, peanut allergy is particularly significant, due to its exceptional severity and frequent lifelong duration. Much of its aetiology remains unclear. In particular, it remains unknown why, unlike other food allergies, peanut allergy incidence correlates poorly with average dietary peanut consumption. A popular explanation for this discrepancy is that peanut allergy is more common in regions where predominantly dry-roasted (DR) peanuts are consumed, leading to speculation that DR-induced chemical modifications may contribute to pathological T_h2 responses in humans. Yet to date, no research group has demonstrated an enhanced immunogenicity of DR peanuts relative to raw in a murine model of sensitisation. This thesis begins with the hypothesis that dry-roasting does indeed alter the chemical composition of peanut proteins in such a way as to increase immunogenicity and allergenicity. To test this hypothesis robustly, I have first addressed flaws in previous studies by developing a methodology to thoroughly characterise samples of raw and DR peanut protein, as well as purifying samples of individual peanut allergens. Using these samples, I have demonstrated an enhanced immunogenicity of DR peanut protein relative to raw, in intragastric, subcutaneous and epicutaneous models of mouse sensitisation, and furthermore, that such enhanced responses feature a pronounced T_h2 bias and functional IgE production. I will present evidence that this difference is not caused by either protein aggregation or the presence of other non-protein substances, but is due to an intrinsic property of the DR peanut proteins. I will go on to clarify candidate molecular mechanisms of this effect, examining several putative receptors and probing the effects of roasting on dendritic cell binding and interactions of peanut proteins. I conclude in light of these investigations that the dry-roasting hypothesis remains the most plausible explanation for the epidemiological distribution of peanut allergy, although many additional questions remain regarding the nature of the chemical modifications produced by roasting and the molecular basis of their recognition by the immune system.

The study aimed to investigate the food safety practices of HACCP and ISO2200 in food establishments in Tanzania, focused on knowledge (awareness) and management practices of food safety systems. The research randomly surveyed 200 food establishments from three regions in the country; only 113 managers completed the survey. Research conducted face-to-face by questioning knowledge (employees and managers), management practices (ISO 22000, HACCP and prerequisites programs, GMP and SSOP), and demographic information. Employees indicated to have more knowledge on the use of GMP (64.3 %) than HACCP (22.9%) and ISO22000 (15.4%) and training of employees was GMP (73.9 %), ISO22000 (19.2 %) and HACCP (27.1%). This knowledge was also measured by frequency of training results, which indicated inadequacy of twice per year almost 31.4 % for manager, and every 3 months (29.1%) employees. Management practices of food safety systems indicated HACCP practices were inadequately done by only 26.6 % of food establishments by validating quality assurance and monitoring systems. This also included the management pratices of barriers and benefits of food safety systems (ISO 22000 and HACCP). Barriers indicated poor confidence in suppliers to provide appropriate raw material (25.7 %), lack of government support (17.3 %) and the least 4% volume of paperwork. While, benefits indicated 68.6 % benefits as the highest with the lowest (22.7%) increase in product price. The improperbarrier implemenatation resulted into inadequate control of hazards under the HACCP program, only 40 % of the food establishments asserted all food in storage was protected from contamination. Prerequisite programs in food establishments were fairly managed, over 80 % had well-designed draining systems within their food establishments.The least (35.5%) had written sanitation standard operation procedure for cleaning and disinfectants. It is suggested that through job training, class training on food safety, and availability of resources, knowledge as well as management practices could be improved within food establishments. Further studies should focus on customer awareness, food vendors as well as single groups within the food industries.

Although ground stone artifacts comprise a substantial portion of the archaeological record, their use as an important source of information about the past has remained underdeveloped. This is especially true for milling tools (mortars, pestles, grinding slabs and handstones) used by hunter-gatherers. Three studies that apply novel techniques and approaches to prehistoric milling technology are presented here. Together they demonstrate that substantial opportunities exist for new avenues of inquiry in the study of these artifacts. The first combines a simple optimization model from behavioral ecology with experimental data to weigh manufacturing costs against gains in grinding efficiency for mobile hunter-gatherers. Results run counter to widespread assumptions that mobile hunter-gatherers should not spend time shaping grinding surfaces on milling tools. Next, gas chromatography-mass spectrometry (GC-MS) is used to analyze lipid preservation in modified rock features in dry caves at Gila Cliff Dwellings National Monument, New Mexico. A high concentration of lipids, derived from processing a seed resource, was recovered from a grinding surface in these caves. The lipid content in this surface is comparable to amounts recovered from select pottery sherds that have been used for radiocarbon dating. The third study uses synchronic and diachronic variability in morphology, use-wear, and symbolic content to analyze ground stone milling tools from mortuary contexts in the San Francisco Bay Area of California. Archaeological and ethnographic evidence supports the inferred association of certain mortars with feasting and ritual activities. Differences in the representation of some of these forms in male and female graves may reflect changes in the roles of women and men in community ritual and politics.

The aim of this thesis is to test the importance and sufficiency of existing constructs of customer service, customer satisfaction and service quality in the logistics function of the UK food processing industry. These activities represent ongoing challenges in the logistics discipline and are under-researched in this industry sector that is affected by primary producer crises, product commoditisation and increasing retailer power. Firms that improve customer service should increase customer satisfaction resulting in better customer-supplier relationships, increased customer loyalty, profitability and a differential competitive advantage. The customer-supplier dyadic exchange between intermediary food processors is the focus of study. There has been little programmatic and integrative study or empirical research of these activities in logistics since work conducted over twenty-five years ago by La Londe and Zinzser. Additionally, some existing studies suffer from a general lack of rigour that pervades the logistics discipline and has prevented meaningful development of research validity and reliability. Finally, existing research into these activities from the marketing discipline is under-utilised in these investigations. Indeed, there has been limited inter-disciplinary research in logistics notwithstanding the genesis of both logistics and marketing as a single discipline at the beginning of the 20th century. This study uses a rigorous two-stage methodology developed for marketing research by Churchill. This methodology comprises generating variables for enquiry from a literature review, collecting and analysing data in a pilot survey to purify variables, and conducting a second survey to assess reliability and validity of pilot study findings. Models used for the study are adapted from existing work in marketing service quality by Parasuraman, Zeithaml and Berry and are supplemented by relationship constructs emerging from the pilot study. A postal survey was administered to 1,215 UK food processors. Respondent data was analysed using exploratory and confirmatory factor analysis and structural equation modelling to test variables and constructs. The findings of this study validate constructs of pretransaction, order service and quality and relationship service and quality, thus reaffirming original constructs developed by La Londe and Zinzser. The findings also falsify transaction service quality constructs posited by Parasuraman, Zeithaml and Berry. Issues of price, supplier importance, supplier switching, and relationship power were tested, but did not feature in resultant constructs. These latter issues are discussed in terms of an overarching framework that encompasses the validated constructs and an extended model is hypothesised for future study. The results of this thesis indicate that UK food processors should consider all phases of pre-transaction, transaction and post-transaction events when facilitating operations design and customer service planning.

Master of Science / Grain Science and Industry / Greg Aldrich / Processing pet food can be beneficial, but can also have adverse effects on shelf-life and nutrient survival. Most affected are supplemental vitamins and essential fatty acids (EFA). Pet food complicates this relative to human foods by combining all elements into the product before processing and requiring an extensive shelf-life (up to 2 years). The objective of this research was to determine the effects of processing, diet, and storage conditions on vitamin (vitamin A, vitamin D₃, vitamin E, folic acid and thiamine) and omega-3 fatty acid (with an emphasis on eicosapentaenoic acid; EPA 20:5n3, and docosahexaenoic acid; DHA; 22:6n3) retention. The research was conducted in two separate experiments. Each experimental diet was produced on a single-screw extruder and triple-pass dryer. Target nutrients were evaluated in premixes in tandem to extruded diets. The vitamin study was conducted as a 3 X 2 X 2 factorial arrangement of treatments with 3 levels of dietary crude protein (CP), 2 screw speeds in the extruder, and 2 levels of time X temperature combinations in the dryer. Vitamins were added at 10 times normal levels to aid in analysis. The EFA study was conducted as a 3 X 3 factorial arrangement of treatments with 3 levels of dietary protein and 3 different omega-3 sources: fish oil, fish meal, or purpose-grown algae rich in DHA. In the vitamin premix study, the quantity of vitamins declined by approximately 50% over 6 months storage in ambient conditions (AMB; 20C, 50%RH), and all except folic acid were lost to some degree in stressed shelf life testing (SSLT; 50C, 70% RH) over 6 weeks. In all cases, the concentration of vitamins in food exiting the extruder and dryer were lower than target levels. As CP increased, the retention was higher (P ≤ 0.05) for vitamins A, E, and folic acid off the extruder (e.g. 225,352 vs. 219,184 and 206,249 IU/kg of vitamin A for high vs. medium and low CP, respectively), and vitamin D₃, E, and folic acid off the dryer (e.g. 9,047 vs. 7,473 and 6,945 IU/kg of vitamin D₃ for high vs. medium and low CP, respectively). During storage of finished pet food in AMB, vitamins A and D₃ were lost (P < 0.05) to the greatest degree (49 and 22%, respectively). The total retention following both processing and AMB storage was 27, 68, 78% for vitamins A, D₃, and E, respectively, while folic acid and thiamine were relatively stable. In SSLT storage, all vitamins except vitamin E were depleted more than 60% (P < 0.05) by 24 weeks, whereas total retention following both processing and SSLT storage was 3, 59, 43, 33, and 7% for vitamins A, D₃, and E, folic acid, and thiamine, respectively. This would suggest that beyond processing losses, the vitamins are relatively stable in premixes and foods if stored in AMB conditions. In the study to evaluate fatty acid stability within a vitamin premix, EPA, DHA, and total omega-3 fatty acids were relatively stable during storage over 6 weeks with losses no greater than 12% in stressed shelf life testing (SSLT; 40C, 70% RH). While in ambient conditions (23C, 50% RH) over 3 months, there was a total loss of EPA, DHA and total fatty acids by 17, 9, and 11%, respectively. Exiting the extruder and dryer, EPA and DHA were not affected by CP level or Omega-3 source. As SSLT storage of finished pet food increased through 24 weeks, EPA, DHA, and total fatty acids declined slightly (P < 0.05; 125, 82 mg/kg for EPA and 77, 60 mg/kg for DHA, and 418, 476 mg/kg for total fatty acids at 0 vs. 24 wk. As time in ambient storage reached 24 months, EPA, DHA, and total fatty acids declined slightly (P < 0.05; 125 vs. 78 mg/kg for EPA and 77 vs. 50 mg/kg for DHA, and 387 vs. 373 for total fatty acids at 0 vs. 24 mo.) Algal-DHA appears to be a stable source of DHA when compared to fish oil and fishmeal. During processing retention of fat soluble vitamins was less than water soluble vitamins, and the omega-3 fatty acids were relatively unaffected. Whereas, vitamins appeared to be more sensitive to temperature during storage and the omega 3 fatty acids more affected by time.

Atualmente, o consumidor está cada vez mais exigente. Além de procurar por produtos que tenham qualidade e conveniência, quer alimentos que sejam seguros do ponto de vista microbiológico e sanitário. Uma alternativa são produtos minimamente processados, que têm valor agregado, são atrativos ao consumidor, e por conseqüência, aumentam o lucro do produtor (e/ou intermediários), além de satisfazerem os desejos do consumidor de adquirir um produto de fácil e rápido preparo e que também apresente inocuidade, sendo que esta última poderia ser garantida por um certificado de rastreabilidade de toda cadeia produtiva do produto. Um sistema informatizado de rastreabilidade para um produto do pescado brasileiro, além de ser uma ferramenta de extrema necessidade, é uma inovação tecnológica, visto que poucos países no mundo avançam nesta direção. A rastreabilidade dos alimentos se apresenta de forma essencial e inevitável, como conseqüência de uma série de incidentes relacionados a segurança alimentar, ocorridas pelo mundo todo, durante os quais, os sistemas de informação disponíveis mostraramse inadequados, ausentes, demorados ou incapazes de assegurar aos consumidores a inocuidade dos produtos. Fica evidente, portanto, que o esforço conjunto dos setores produtivos e do governo para implementar e viabilizar o processo de rastreabilidade é um passo fundamental para garantir ao Brasil uma posição de destaque no cenário internacional do agronegócio. Dessa forma, a presente pesquisa teve como objetivo oferecer subsídios para tornar viável o desenvolvimento de um sistema informatizado de rastreabilidade aplicado à cadeia de produção de tilápia minimamente processada. Sendo assim, pretendeu-se padronizar o produto e o processo de obtenção de filés de tilápia (Oreochromis niloticus) minimamente processados refrigerados e embalados a vácuo. Para tal, fez-se necessário: determinar as etapas de produção, através do aferimento de todas as etapas envolvidas na cadeia produtiva; e protocolar um padrão de identidade e qualidade para este produto advindo da piscicultura. Esses dados poderão fornecer os parâmetros para possibilitar, em pesquisas futuras, a rastreabilidade do produto, partindo da qualidade da matéria-prima até o alimento embalado para consumo. Este trabalho integra um conjunto de 5 (cinco) subprojetos que compõem o projeto: Rastreabilidade da cadeia produtiva de pescado cultivado tilápia (Oreochromis niloticus), financiado pela FINEP/FUSP, sob o edital Aqüicultura Ação transversal 12/2005. / Currently, the consumer is increasingly demanding. In addition to searching for products with quality and convenience, they search products with standards of hygiene and microbiology. An alternative in the segment of convenient foods is fish minimally processed, which have value added, are attractive to consumers, and consequently, increase the profit of the producer (and/or intermediaries), in addition to meeting the desires of the consumer to purchase a product for easy and fast preparation and also provide safety, and that it could be guaranteed by a certificate of traceability throughout the production chain of the product. A system of traceability for a product of Brazilian fish, besides being a tool of extreme need, is a technological innovation, since few countries in the world are moving towards this direction. The traceability of food is so essential and inevitable, as a result of a series of food safety incidents that occurred throughout the world during which, the information systems available have proved inadequate, absent, or unable to provide lengthy to the safety of consumer products. Therefore, it is evident that mutual efforts from both the government and producers to implement and make a traceability process viable are a critical step forward to grant Brazil a position of reference in the agribusiness international scenario. Thus, the present research aimed to offer basis to provide viability for the development of a computerized traceability process applied to the production chain of tilapia minimally processed. This way, it is aimed to standardize the product and the process to obtain the tilapia (Oreochromis niloticus) minimally processed. To do so, it is needed to: determine the phases of production, through the improvement of all steps involved in the production chain and establish quality and identification standards for the product deriving from fish farming. These data may provide the parameters to allow, in future research, the traceability of the product, starting from the raw material to the end wrapped product, including product labeling and also the possible ways to locate its paths along the distribution chain. This plan is part of 5(five) sub-projects which comprise the whole project: Traceability of production chain of farmed fish tilapia (Oreochromis niloticus), sponsored by FINEP/MCT/SEAP edital aquaculture Ação Transversal 12/2005.

Carragenanas, agaranas e alginatos são hidrocolóides largamente utilizados em todo tipo de produtos alimentícios como aditivos espessantes. Eles não são absorvidos pelo organismo e, portanto não introduzem calorias extras na dieta. A irradiação se apresenta com grande potencial como um método alternativo na preservação de alimentos pois não induz aumento da temperatura, e é, portanto, de grande eficácia na descontaminação de ingredientes alimentícios sensíveis ao calor. Neste trabalho, soluções dos hidrocolóides agararana, carragenana e aiginato de sódio, foram irradiadas com diferentes doses (0-10 kGy) de radiação gama de Co-60 na presença de antioxidantes também utilizados na indústria alimentícia: ácido ascórbico, extrato vegetal de rosela (Híbiscus sabdariffa L.) e isofiavona de soja. As soluções dos polissacarídeos comestíveis agarana, carragenana e alginato de sódio mostraram ser bons sistemas para avaliar o efeito da radiação ionizante por apresentarem radiossensibilidade característica medida pelas mudanças na viscosidade. Os resultados obtidos mostram que esses antioxidantes apresentam, no geral, ação radioprotetora o que pode ser de grande valia nas aplicações futuras da irradiação de alimentos em escala comercial. / Carrageenan, agaran e alginates are hydrocolloids largely employed in every kind of food products as stabilizing agent and viscosity builder. The human body does not absorb them, so they do not introduce extra calories in the diet. Irradiation is presented as an important alternative method in food preservation because do not induce temperature increase being of good efficiency in cold food ingredients decontamination. In this work aqueous solutions of carrageenan, agar e sodium alginate were gamma irradiated (0-10 kGy) in presence of ascorbic acid, roselle {Hibiscus sabdariffa L.) extract and soy isoflavone. Edible polysaccharide solutions showed to be suitable systems for the evaluation of ionizing radiation effects as they presented a singular radiosensitivity through viscosity changes. The results obtained showed that in general the antioxidants employed had a radioprotective action that can be of importance in the future commercial applications of food irradiation.

A demanda por produtos industrializados que apresentem máxima preservação de suas características naturais têm crescido e feito as indústrias alimentícias re-analisarem seus processos para atingirem essa necessidade do mercado. A abordagem convencional conservadora, utilizada para o dimensionamento do processamento térmico de alimentos, pode levar ao sobre-processamento especialmente no regime laminar, devido às significativas distribuições de temperatura e tempos de residência existentes. Um modelo matemático, composto por equações diferenciais de massa e energia foi elaborado, considerando o processamento térmico de um fluido não-newtoniano, sob regime laminar, escoando em um trocador de calor bitubular. No modelo, se levou em conta as dispersões efetivas de massa e energia associadas com o escoamento laminar não ideal, as trocas de calor com o ambiente, a letalidade que ocorre no aquecimento e resfriamento e o perfil de velocidade. O modelo foi testado por meio de simulações do estudo de caso do processamento térmico de suco de graviola (fluido pseudoplástico) considerando a destruição de bolores e leveduras. Objetivou-se nas simulações avaliar o efeito de distintas considerações do modelo nas variáveis consideradas. Os resultados indicaram que as etapas de aquecimento e resfriamento contribuíram de forma significativa na letalidade do processo, assim como as considerações quanto às dispersões de massa e energia. Como exemplo, as letalidades, considerando a abordagem convencional (tubo de retenção isotérmico com velocidade máxima) e o modelo completo (com todas as considerações) apresentaram valores de 1,46 e 5,74, respectivamente. A flexibilidade do modelo elaborado, assim como os tempos computacionais pequenos necessários para obter os resultados são as principais vantagens do uso do mesmo. Acredita-se que o modelo elaborado pode contribuir de forma importante para o correto dimensionamento e avaliação de processos térmicos em indústrias de alimentos, permitindo que a demanda dos consumidores seja atendida. / The demand for industrialized food with maximum retention of sensorial and nutritional attributes has grown and made the food industries rethink operational conditions to meet this market expectation. The classic conservative approach, used for the design of thermal food processing can lead to over-processing specially in laminar regime, due to the existing significant temperature and residence time distributions. A mathematical model, comprising differential equations for mass and heat transfer was elaborated, considering the thermal processing of a non-Newtonian liquid, under laminar flow in a double-pipe heat exchanger. In the model, it was taken into account the effective mass and energy dispersions associated with the non-ideal laminar flow, the heat exchange with the ambient, the contribution from heating and cooling sections in the lethality and the velocity profile. The model was tested through simulations of a study case of soursop juice processing (pseudoplastic fluid) regarding the destruction of yeast and molds. The objective of the simulations was to evaluate the effect of distinct model assumptions on the variables. The results indicated that the heating and cooling sections and the assumptions regarding the effective mass and energy dispersions had an important contribution to the processing lethality. As an example, the lethality, regarding the conventional approach (isothermal holding tube at the maximum velocity) and the complete model (with all the assumptions) were 1.46 and 5.74, respectively. The model flexibility and the small computational time needed for the results to the obtained are the main advantages of its use. It is expected that the developed model can be an important contribution to the correct design and evaluation of thermal processing in food industries, allowing the consumer demands to the reached.