Young Scientist Award Winners - IUFoST World Congress, Montreal, Canada, August 2014

Recognizing Excellence in Food Science and Technology

"These Young Scientists exemplify excellence in the food science and technology profession, and the award demonstrates IUFoST's ongoing commitment to nurturing the next generation of food scientists," says Dr. Pingfan Rao, President of IUFoST. "They join a small and select list of Young Scientists who have received this prestigious award since its inception eight years ago. We look forward to introducing the winners and their work to the world."

The 2014 Young Scientist Award recipients are all under the age of 35 and are working in their first post-doctoral or academic positions. The award is based upon their research, which must have an international application reflecting the Congress theme of Research That Resonates, along with recommendations from other professionals. 

Christine Pin Rou Lee, Singapore

Modulation of Papaya Wine and Durian Wine Flavour Compound Formation by Yeast

Introduction

For decades, grapes have been used as the raw material for the production of wine. However, in the tropical region, there are a variety of fruits which are potentially suitable for making good quality fruit wines, but remain unexploited because of a lack of research and development as compared to grape wine. Papaya (Carica papaya) and durian (Durio zibethinus Murr.) were chosen for this study, owing to their rich phytochemical and antioxidant contents besides sugar contents, together with their rapid postharvest deterioration. Fermentation provides an alternative for the processing of these fruits. This project assessed the biotransformation of volatile and non-volatile papaya and durian constituents with a focus on volatile compounds during fermentation with mono- and mixed-culture of Saccharomyces cerevisiae and Williopsis saturnus, in view of developing “papaya wine” and “durian wine” as new tropical fruit wines.

Methodology

Laboratory-scale fermentations were carried out in papaya juice and durian pulp separately, using mono- and mixed-cultures of Saccharomyces cerevisiae and Williopsis saturnus at a ratio of 1:1000. Oenological parameters (pH, oBrix, sugars and organic acids) and yeast cell counts were determined during fermentations. Volatile compounds were analysed and quantified by headspace-solid phase microextraction with gas chromatography-mass spectrometry-flame ionisation detector (HS-SPME-GC-MS/FID). Principal components analysis (PCA) was applied to volatile data to discriminate the typical volatile profile of the wines.

Result

S. cerevisiae was  the  main  producer  for  medium- to  long-chain  fatty  acids, alcohols,  ethyl  esters  and  terpenoids,  whereas  W.  saturnus produced high levels of acetate esters. A diversity of volatiles was produced especially alcohols and esters, while those volatiles initially present in papaya and durian were either utilised or transformed. Volatiles  that  were  initially  present  in  the  papaya  juice,  especially benzyl  isothiocyanate,  butyric  acid,  benzaldehyde  and  β-damascenone  were metabolised to trace levels during fermentation. Similarly, the character-impact sulphur-containing odorants (typically sulphides) in durian decreased with fermentation. Some sulphur-containing compounds in durian wine fermentation were produced, such as 3-(ethylthio)-1-propanol that was produced initially then remained relatively stable, whereas ethyl thioacetate was formed initially then decreased in all culture types. The mixed-culture fermentation of S. cerevisiae and W. saturnus in papaya and durian benefited differently from the presence of both yeasts. In the papaya wine mixed-culture fermentation, there was higher production of acetate esters than the S. cerevisiae monoculture, and higher concentrations of alcohols and ethyl esters than the W. saturnus monoculture. The mixed-culture also produced utmost levels of aroma-active  esters  such  as  ethyl  hexanoate,  ethyl  octanoate  and  ethyl  decanoate (pleasant fruity, estery and floral aroma) in papaya wine. As for the durian wine, higher amounts of alcohols were produced in the mixed-culture than those from the S. cerevisiae monoculture.

Conclusion

This study has demonstrated the potential of the evaluated yeast strains to ferment papaya juice and durian pulp. The dynamic biotransformation of papaya and durian constituents and evolution of the volatile compounds led to differences in flavour profiles among the different cultures. As compared to the mono-culture, the mixed-culture had enhanced volatiles and flavour complexity. The exploitation of mixed-culture of S. cerevisiae and W. saturnus in the biotransformation of papaya juice and durian pulp has provided an alternative use of papaya and durian fruits, and may create a new industrial outlet for these fruits. This may also be useful for winemakers in creating novel fruit wines with flavour complexity and distinct style.

Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 3, Singapore 117543, e-mail: Christine.lee@shirocorp.com . ∗ The PhD research was conducted under the supervision of Dr Shao Quan Liu at the National University of Singapore.

George Ooko Abong' Kenya

Dietary Acrylamide Exposure of the Kenyan Population: Case Study of Potato Crisp Consumers in Nairobi

Abstract

Acrylamide is a heat induced possible human carcinogenic chemical resulting from irreversible combination between reducing sugars and the amino acid asparagine especially when foodstuffs are cooked at temperatures of 120oC and above. Since plant foodstuffs such as potato have high asparagine content, acrylamide tends to be high in fried potato products such as French fries and potato crisps. Potato crisps for instance provide between-the-meal snacks to many consumers all over the world including Kenya. This study was intended to assess the exposure to acrylamide by assessing consumption of potato crisps in Nairobi, Kenya, where processing parameters, process controls and varieties used are different from those in countries where such data have been generated.

A potato crisps consumption survey was carried out among crisps consumers. The data were collected from consumers from the retail outlets where they bought the crisps. Consumption data were combined with contamination data arising from analysis of crisps at retail outlets and street processors in the same region and dietary acrylamide exposure was calculated using a probabilistic approach.

The mean acrylamide intake was 1.57µg/kg bw/day while the 95th (P95) percentile was 5.1µg/kg bw/day with margins of exposures (MOE) being respectively 197 and 61. The acrylamide intake was significantly higher in street processed crisps (non-branded) with a mean value of 2.26 µg/kg bw/day and 95th percentile of 6.54 µg/kg bw/day, and MOE being respectively 137 and 47.

The extremely lower MOEs indicate higher exposure to acrylamide by the consumers mainly due to higher contamination levels. Important steps are therefore required to mitigate the high exposure by reducing levels of acrylamide contamination and decreasing consumption.

Dr George Ooko Abong' is a Lecturer and Industrial Training Coordinator, Department of Food Science, Nutrition and Technology, University of Nairobi, Box 29053, Nairobi, Kenya; e-mail: georkoyo@yahoo.com  or ooko.george@uonbi.ac.ke

Co-authors JA Ogolla and MW Okoth are with the Department of Food Science, Nutrition and Technology, University of Nairobi; JN Kabira is with the National Potato Research Centre, KARI, Tigoni, Box 338, Limuru, Kenya; and PN Karanja is with the  Department of Food Science and Technology, Jomo Kenyata University of Agriculture and Technology, Box 29000, Juja, Kenya

Kai Reineke, Germany

Innovative Sterilisation Technologies for Increased Consumer Safety and Product Quality

Introduction

The consumer’s demand for high quality food has increased drastically. To meet this goal and to guarantee food safety, various different preservation methods have been developed. Many of the traditional technologies rely on the inactivation of microorganisms, in which microbial safety is usually only made possible by increasing the process intensity, which is often accompanied by a decrease in the nutritional value and sensory properties. To overcome these unwanted side effects, high pressure processing (HPP) and pulsed electric fields (PEF) are often regarded as the major recent technological innovations in food preservation. However, these technologies are only applied in large scale for pasteurisation and not for sterilisation, which is largely due to the unknown inactivation mechanisms of highly resistant bacterial endospores.

Methodology

Detailed germination and inactivation studies with Geobacillus stearothermophilus and Bacillus subtilis spores as well as isogenic mutant strains, were done within a wide pressure-temperature-time domain (20-130 °C and 0.1–1200 MPa). For spore inactivation by PEF, a combination of preheating (up to 90 °C) and an insulated PEF-chamber combined with a holding tube (65 cm) and a heat exchanger for cooling, enabled a rapid heat up to 105 to 140°C (measured above the PEF chamber) within 92.2-368.9 µs. After the treatments the physiological state of the spores was analysed using plate count methods and flow cytometry and the amount of released dipicolinic acid from the spore core was quantified by HPLC. Further a focused ion beam section method was developed to analyse the internal structures of the spores after the treatments.

Results and Discussion

Based on this set of methods and multi-response kinetic modeling, detailed pathways of spore germination and inactivation during HPP were proposed. A clear differentiation between nutrient like and non-nutrient pressure induced germination was found and a threshold pressure of 600 MPa identified above which the process temperature dominated the germination and inactivation rate. Under these conditions, the inner spore membrane seems to be the target structure for spore inactivation.

A synergistic effect on spore inactivation was also found for a combination of moderate preheating and PEF. A preheating to 95°C and an energy input of 144 kJ/kg resulted in an outlet temperature of 126°C and a 3.28 log10 inactivation of G. stearothermophilus spores, whereas nearly no inactivation (0.2 log10) was achieved during the thermal treatment. Due to the insufficiency of the calculated residence time and temperature field (calculated with Comsol Multiphysics) to induce a thermal damage of the inner spore membrane, a different inactivation mechanism must be present.

Conclusions

The kinetic data and proposed inactivation mechanisms can aid in optimising these innovative sterilisation technologies and will increase consumer safety. Combinations of different extrinsic factors like HPP and/or PEF with chemical or thermal preservation may open up the possibility of establishing a multi-target inactivation strategy for food sterilisation.

Dr Ing. Kai Reineke is with Quality and Safety of Food and Feed, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Max-Eyth-Allee 100, 14469 Potsdam, Germany; e-mail: kreineke@atb-potsdam.de

Patrick Njage, South Africa

Pathogenic and Commensal E. coli from Irrigation Water Show Potential in Transmission of Extended Spectrum and AmpC β-Lactamase Determinants to Lettuce Contaminants

Introduction and Objectives

E. coli are able to acquire and produce extended-spectrum and AmpC β-lactamases (ESBL/AmpC) which hydrolyse important new-generation β-lactam antibiotics. Many studies report occurrence of these enzymes in food animals. Little attention has been given to occurrence of ESBL/AmpC in vegetables and role of production environment though many vegetables are consumed raw leading to enhanced exposure. We studied the occurrence of ESBL/AmpC in E. coli producing from lettuce and the role of irrigation water in resistance transmission.

Methods

ESBL/AmpC in E. coli isolated from two irrigation water sources over ten months (n = 46) were typed by PCR and sequencing. Typing was also done for genetic similarity and phylogeny which classified strains as either commensal or potential pathogens.

Results

The ESBL/AmpC profiles differed significantly with the source (χ2 (6, N = 43) = 39.4, p < 0.001). ESBLs/ AmpC were detected in 35 isolates (76%). Fourteen isolates (30%) produced both an ESBLs/AmpC. Prevalence was highest in E. coli from lettuce (90%). Twenty two isolates (48 %) harboured between two and five ESBL/AmpC genes. Major ESBL determinants were CTX-M type (34 isolates). DHA (33% of isolates), CIT (28% isolates) and ACC (24% of isolates) were the dominant AmpC B-lactamases. A high degree of genetic relatedness between E. coli from irrigation water and lettuce indicated common ancestry and pathway of transmission. Three similar clusters of E. coli from lettuce and irrigation water and two clusters from lettuce exhibited similar ESBL/AmpC determinants. Differences in ESBLs/ AmpC profiles were also noted in strains from similar clusters in 7 out of 8 clusters. Phylogenetic grouping indicated that 29% of strains belonged to the potentially extraintestinal pathogens from groups D and B2. The phylogenetic profiles when compared with those reported from humans indicated possible human origin of the E. coli.

Conclusions

ESBLs/ AmpC bearing E. coli from irrigation water likely contribute to ESBL/AmpC in contaminated lettuce though transfer of mobile genetic elements and direct transfer of strains from irrigation water. Phylogenetic profiles link human contamination with ESBL/AmpC determinant harbouring E. coli in lettuce production environment. This data will enable further quantification of the risk posed to humans from the transfer of ESBL/AmpC determinants and test of possible mitigation strategies for consumer protection.

Dr Patrick Njage , Patrick Kamau and Professor EM Buys are with the Institute for Food, Nutrition and Well-being, Department of Food Science, University of Pretoria, South Africa; e-mail patrick.njage@up.ac.za

Amy Proulx, Canada

Innovating on the Academic Research Model - How Client Driven Applied Research Reaps Returns for Small and Medium Sized Food and Beverage Companies

Purpose

Small and medium sized enterprises (SMEs) are the largest area of job growth and innovation in the Canadian food and beverage sector. The biggest barriers to innovation in smaller companies come from lack of access to technical resources for successful product development, along with limited expertise to ensure market readiness and commercialisation. Most small companies have applied research needs, which require a more entrepreneurial and commercial approach. A client driven strategy focuses on the needs of the company, and retains intellectual property with the company allowing for them to leverage knowledge for growth. Research of this type, however often benefits from being conducted in an academic setting, leveraging resources, funding and expertise unique to academia.

Client-driven research requires a unique academic approach, and a different academic business model.

Key Findings

The Canadian Food and Wine Institute Research Centre is a Natural Science and Engineering Research Council - College and Community Innovation Program Funded Centre, where industry partners drive innovation, and access technical resources and government innovation funding through novel partnerships. The research team from the Centre acts primarily as solutions providers for the industry partner. Equally vital to the Centre's success is the education and training component, where industry clients are encouraged to actively engage in the research process as a means of empowerment, with the intent that they will in the future conduct more of their research objectives independently, and thereby promote job creation. This client-driven approach is critical for innovation that helps SMEs grow.

Dr Amy Proulx is with the Canadian Food and Wine Institute at Niagara College, 135 Taylor Road, Niagara on the Lake, Ontario, Canada; e-mail: aproulx@niagaracollege.ca  

Uthaiwan Suttisansanee, Thailand

The Investigation on Optimised Extraction Conditions, Total Phenolic Contents and Antioxidant Capacities of Gynura procumbens and Gynura divaricata Leaf Extracts

Gynura genera, especially G. procumbens and G. divaricata, are folk medicinal plants, which can be customarily consumed as side dish vegetables in Thailand. Gynura has been investigated regarding its potential health benefits with potentially protective effects toward oxidative stress related diseases. Even though both species possess similar anatomical traits, the quantity and quality of their bioactive compounds may be varied. These differentiations may lead to misuse and confused applications between species. Therefore, the proper usage on effectiveness of active ingredients in each species should be taken into consideration. The objective of this study was, thus, to investigate the optimized extraction conditions of G. procumbens leaf extract (GPE) and G. divaricata leaf extract (GDE) and to compare the antioxidant capacities and total phenolic contents (TPC) between these species.

The extraction conditions were investigated using response surface methodology. The antioxidant capacities were determined using ferric reducing antioxidant power (FRAP) assay and oxygen radical antioxidant capacity (ORAC) method, while TPC was analysed using Folin-Ciocalteu reagent.

The extraction conditions for GPE could be optimised under extraction time of 6 minutes, extraction temperature of 50 °C, liquid-to-solid ratio of 35% (v/w) and extraction solvent of 51% (v/v) aqueous ethanol. Likewise, GDE could be extracted under extraction time of 15 min, extraction temperature of 53 °C, liquid-to-solid ratio of 47% (v/w) and extraction solvent of 61% (v/v) aqueous ethanol.

Under these extraction conditions, antioxidant capacities of GDE were found to be significantly higher than those of GPE. The HPLC results indicated that GDE possessed higher levels of caffeic acid and quercetin than those of GPE, while similar quantities of p-coumaric acid and kaempferol were detected. However, TPC of GPE was higher than that of GDE. Since most phenolics could function as antioxidants, these results possibly suggested that the quantity of total phenolics was greater in GPE, but GDE might contain stronger antioxidants. The information received from this research would extend fundamental knowledge on methodology of optimised extraction conditions of antioxidants and phenolics from GPE and GDE. Besides, GDE possessed stronger antioxidants than GPE, possibly leading to a greater efficient source to fight against oxidative stress-related diseases.

Dr Uthaiwan Suttusansanee and co-authors Triwoot Phanyotha, Parunya Thiyajai, Warangkana Srichamnong, Chalat Santivarangkna and Nattapol Tangsuphoom are with the Institute of Nutrition, Mahidol University, Phutthamonthon 4 Road, Salaya, Phutthamonthon, Nakhon Pathom, Thailand 73170, e-mail: uthaiwan.sut@mahidol.ac.th

Ambati Rango Rao,  Malaysia

Production of microalgal carotenoid pigments for  health food applications: Biomass production, pigment  characterization and  analyses of  biological activities

Summary

I In recent years, there is an increasing demand for natural pigments in foods, feeds, nutraceuticals, and pharmaceuticals  for the cosmeceutical industry. Pigments such as β-carotene, astaxanthin, lutein, and other carotenoids are the molecules of implication in treating nutritional deficiencies and life style related disorders.  These molecules have the capacity to quench free radicals and protect the cells from oxidative damage. In addition, carotenoids are also used in animal feed, as a pigment source in aquaculture to improve consumer perception of quality. The current research is related to finding new and safe pigments from natural resources for various health applications. According to the business reports, the global market for carotenoids alone would reach 1.2 Billion US $ by 2015.  In this context our current research on mass production and utilisation of selected microalgae for the carotenoids production is of great significance. 

We were successful in developing cultivation methods for scale-up of Haematococus pluvialis  in photobioreactors and also raceway ponds to enhance biomass productivity with high pigment production. Downstream processing of astaxanthin and its esters was successfully done and the pigments were characterised by various analytical methods, viz HPLC, LC-MS and NMR, and further their biological activities (bioavailability, antioxidant, anticancer, anti-hepatoprotective properties) were evaluated  which are of relevance to health food applications.  The maximum pigment production was obtained from Haematococcus which was evaluated for potential biological activities using in vitro  human cell culture models using glioma cell lines, liver hepatocellular carcinoma cells , and in vivo studies. Further, these pigments may be converted into vitamin A and also can be of use for treating vitamin A deficiency (VAD) which is a global public health problem, particularly in developing countries.

Dr Ambati Ranga Rao is a Senior Research Fellow, Institute of Ocean and Earth Sciences, University of Malaya, Kuala Lumpur, Malaysia-50603, e-mail: arangarao@um.edu.my  or  arangarao99@gmail.com . The supervisor was Prof.  G.A. Ravishankar, Vice-President, R&D (Life Sciences) and Professor of Biotechnology, Dayananda Sagar Institutions, Dr CD Sagar Center for Life Sciences, Bangalore- 560 078, Karnataka, India, email: rgokare@yahoo.co.i

Miguel Cerquiera, Portugal

Effect of Structure and Concentration of Gelator on Organogel Properties: A Rheological and Small­angle X­ray Spectroscopy Study

Organogels are solid­like systems structured in an organic solvent due to molecular interactions of the gelator; their structure network will depend on the concentration and structure of the gelator. Aiming at evaluating the influence of gelator structure and concentration on organogel properties, rheological analyses, polarised microscopy and small­angle X­ray spectroscopy (SAXS) were performed. Four different gelators (glyceryl tristearate­­GT; sorbitan tristearate­­ST; sorbitan monostearate­­SM; glyceryl monostearate­GM) were tested in a medium­chain triglycerides (MCT) oil phase. Organogels were prepared by mixing the oil phase and gelator at different concentrations (5, 10, 15, 20 and 25% [w/w]) at 80 °C during 30 min. Flow curves were obtained using shear rate values ranging from 0 to 300 s−1 and frequency sweeps were done from 0.01 to 10 Hz with 1% deformation. Micrographs were obtained under a polarised light microscope equipped with a digital camera, being samples pre­prepared directly in the support. Small angle X­ray scattering (SAXS) measurements were performed using a synchrotron beamline.

All organogels presented birefringence confirming the formation of a crystalline structure that changes with the increase of gelator concentration. Organogels produced with GT, ST and GM as gelators presented a pattern characteristic of a lamellar structure, while organogels using SM as gelator showed a rod­like structure. Microscopic observations were confirmed by SAXS analyses through log­log SAXS curves at low angles, where the three­dimensional structure of the organogels was confirmed (i.e. rods for SM organogels and flat disks to GT, ST and GM). Through the evaluation of SAXS peaks following Braggs Law it has been shown that all structures were organised as lamellas but with different d­spacings. These particularities at micro­ and nanoscale level lead to differences in rheological properties of organogels. As example for ST and SM organogels all the rheological analyses show a gel­like behaviour (i.e. G' > G''), however for GT and GM organogels this behaviour is not always observed. Organogels produced with GM gelator showed the strongest structure, with high values of G' and G'' (around 60 MPa for 25% of gelator). Results also showed that the hydrophobic chain (stearic acid) and hydrophilic head of gelators influence the three­dimensional network of the organogels, indicating the possibility of tailoring the functionality of organogels.

Dr Miguel Cerqueira is with the Laboratory of Industry and Process, Centre of Biological Engineering, University of Minho, Campus de Gualtar - 4710-057 Braga, Portugal, email: miguelcerqueira@deb.uminho.pt  or  miguelribeirocerqueira@gmail.com