Update on the development of virus-resistant papaya: virus-resistant transgenic papaya for people in rural communities of Thailand

Papaya (Carica papaya L.) is one of the most important and preferred crops in rural communities in Thailand. Papaya ringspot virus (PRSV) is a serious disease of papaya throughout Thailand. Efforts to control the virus by various methods either have not been successful or have not resulted in sustainable control. In 1995, collaborative research by the Department of Agriculture of Thailand and Cornell University to develop transgenic papaya resistant to PRSV was initiated. Two local Thai cultivars were transformed by microprojectile bombardment with the use of a nontranslatable coat protein gene of PRSV from Khon Kaen. Numerous kanamycin-resistantplants were regenerated and were inoculated with the PRSV Khon Kaen isolate for selection of resistant lines. Since 1997, promising RO transgenic lines have been transferred to the research station at Thapra for subsequent screenhouse tests and selection of the most PRSV-resistant lines. In selection set 1, three R3 lines initially derived from Khaknuan papaya showed excellent resistance to PRSV (97% to 100%) and had a yield of fruit 70 times higher than nontransgenic Khaknuan papaya. In selection set 2, one R3 line initially derived from Khakdam papaya showed 100% resistance. Safety assessments of these transgenic papayas have so far found no impact on the surrounding ecology. No natural crossing between transgenic and nonmodified papaya was observed beyond a distance of 10 m from the test plots. Analysis of the nutritional composition found no differences in nutrient levels in comparison with the nonmodified counterparts. Molecular characterization by Southern blotting revealed three copies of the transgene presented; however, no coat protein product was expressed. Data on additional topics, such as the effects offeeding the transgenic papaya to rats and the stability of the gene inserts, are currently being gathered.     

Bt抗虫基因在作物中的应用

基因工程是现代生物技术在生物农药研制方面的重要手段之一,其中以苏云金芽芽孢菌（Bt）杀虫蛋白为基础的转基因作物是该类研究的热点。由于转Bt基因作物在抗虫、减少化学污染方面的良好性能,玉米、棉花等转基因作物已在世界范围内商业化。我国转Bt基因作物研究起步晚,但发展迅速。目前已先后批准了甜椒、番茄以及番木瓜3种作物作为商业化生产。与此同时,Bt转基因作物在基因漂移、抗虫性以及生物安全性方面存在争论,需要更多的实验支持和更深入细致的研究。     

PRODUCT DEVELOPMENT AND NUTRACEUTICAL ANALYSIS TO ENHANCE THE VALUE OF DRIED FRUIT

ABSTRACT

Value‐added fruit products suitable for production by small‐scale farmers and processors were developed and evaluated. Apples, blueberries, peaches and strawberries from local growers were processed into a dried fruit product. The total phenolics, total anthocyanins and oxygen radical absorbing capacity (ORAC) were determined. Drying the fruit concentrated total phenolics, total anthocyanins and ORAC levels as compared to fresh fruit. The nutraceutical components of the blueberries, peaches and strawberries of the local dried fruit were higher than those of commercial dried fruit purchased at a natural food store. The dried fruit from both the local and commercial fruits was used to create a fruit pie filling for consumer evaluation. Consumer acceptance of fruit pie filling from dried fruit grown locally and dried commercial fruits was evaluated using a 9‐point verbal hedonic scale and a 5‐point Just About Right scale. In terms of consumer evaluation, the pie fillings made from local dried fruits were either better or at parity with those from commercial products. In addition to the nutraceutical benefits, the pie fillings were consumer acceptable products that could represent an avenue for small‐scale farmers to add value to surplus fruit.

PRACTICAL APPLICATIONS

Complete utilization of fruit crops is a key component to the success of small farm operations. Excess fruit crops can be dried (or processed in other manners) and used to create many value‐added products. Increased consumer awareness of healthy food products provides a niche market for these fruit products. In this research, the nutraceutical benefits of fresh and dried apples, blueberries, peaches and strawberries were investigated and the consumer overall acceptance of a pie filling produced from these dried fruit was shown.

     

我国食品转基因标识研究

21世纪是生物技术的世纪,转基因食品的研究与开发已经成为学术界乃至广大公众的话题。转基因作物的成本低、产量高;具有抗除草荆、抗虫和抗病毒等特性;提高转基因食品的品质和营养价值;转基因食品便于运输、贮藏;增加保鲜性。转基因食品在给人类带来巨大效益的同时也存在着各种风险以及问题。转基因食品是否安全?转基因食品是否应该进行标识?对转基因食品应该如何标识才能保障广大消费者利益?本文正是在这一大背景下。在论证转基因食品标识必要性的基础上论述了美国和欧盟两大发达国家的标识制度;分析了我国转基因食品标识制度的现状,同时借鉴发达国家经验指出了转基因食品标识所存在的问题并在此基础上提出了一系列建议措施。     

Current trends of tropical fruit waste utilization

Recent rapid growth of the world's population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.     

New developments in Biotechnology—an overview

人类运用生物技术已经几千年了。直到上个世纪，发酵方法生产啤酒、白酒、面包、酱油以及其它食品都是在农产品领域的主要应用。自从50年前DNA和RNA结构和作用被揭示以来，一场生物技术的革命便产生了，并导致了两项关键技术的发展：1）通过基因技术进行遗传因素的修改；2）新型快速多样分析工具；最新的发展都基于遗传学。这篇文章我将探讨以下问题：遗传因子修改的进展和公众认可的争论；基因学技术在农产品领域的应用；我的TNO研究所与中国伙伴联合的生物技术项目的例子；谷物科技方面的生物技术。     

Commercial bacterial starter cultures for fermented foods of the future

Starter cultures for fermented foods are today developed mainly by design rather than by screening. The design principles are based on knowledge of bacterial metabolism and physiology as well as on the interaction with the food product. In the genomics era, we will obtain a wealth of data making design on a rational basis even simpler. The design tools available are food grade tools for genetic, metabolic and protein engineering and an increased use of laboratory automation and high throughput screening methods. The large body of new data will influence the future patterns of regulation. It is currently difficult to predict in what direction the future regulatory requirements will influence innovation in the food industry. It can either become a promoting force for the practical use of biotechnology to make better and safer products, or it can be limiting the use of starter cultures to a few strains with official approval. Successful cultures based on modern technology is expected to be launched in the areas of: probiotics, bioprotection, general improvement of yield and performance for the existing culture market and probably the introduction of cultures for fermenting other food products. A scientific basis for dramatic innovations that could transform the culture industry is currently being established.     

An interdisciplinary and participatory methodology to improve user acceptability of root,tuber and banana varieties

Breeding programmes for root, tuber and banana (RTB) crops have traditionally considered consumer demand for quality characteristics as low priority against other considerations such as yield and disease resistance. This has contributed to low levels of adoption of new varieties and its potential benefits. To address these challenges, an interdisciplinary five-step methodology was developed to identify demand for quality characteristics among diverse user groups along the food chain. The methodology includes an evidence review, consultations with key informants and rural communities, processing diagnosis with experienced processors and consumer testing in urban and rural areas. Quality characteristics are then prioritised into a Food Product Profile by user group to inform further work of biochemists and breeders in developing improved selection tools. This initiative presents a new basis to understand consumer preferences for RTB crops. The methodology is currently being applied in projects in sub-Saharan Africa and is applicable globally.     

An overview of papaya seed oil extraction methods

Papaya seeds account for about 20% of the total fresh fruit weight. The seeds are generally discarded as agricultural waste products during fruit processing despite being edible. The seeds contain high levels of lipid and thus can be a new source of edible oil. Numerous technologies have been used for extraction of crude oil from papaya seeds. Papaya seed oil is composed mostly of unsaturated fatty acids with oleic acid being the major one. The oil also contains lipophilic phytochemicals such as tocopherols, phytosterols and carotenoids. Further investigations are necessary to validate the functional properties of papaya seed oil produced from different extraction techniques.     

Research and development of transgenic plants in Malaysia: an example from an Asian developing country

In 2000, agriculture contributed 13% to the national gross domestic product of Malaysia. The country of 23 million people has created a competitive program coordinated by the Ministry of Science, Technology and the Environment, research institutions, and universities to undertake biotechnology research in several areas. Intensified research efforts are under way on oil palm, rubber, rice, papaya, and orchids. Although the most progress has been made in rice and papaya, no transgenic crop is ready for field trials. Nonetheless, preliminary steps have been taken to prepare for the trials, and detailed testing protocols are being developed.     

THE EVOLVING IMPACT OF BIOTECHNOLOGY ON FOOD MICROBIOLOGY1

The tools of modern biotechnology are being increasingly adapted by food microbiologists. Genetic probes and monoclonal antibodies have become accepted methods for detecting pathogens and toxins in food. The success of molecular genetic approaches to the problems of traditional fermentations has provided the food safety community with a model for decreased reliance on plate counts and new emphasis on the activity and products of deleterious microorganisms. As the emphasis in all biological sciences becomes increasingly molecular, all microbiologists will come to share the same toolbox- a toolbox in which biotechnology comprises only some of the available tools. In the future, these tools may make it possible to genetically engineer resistance to pathogenic microbes into foods.     

How chemophobia affects public acceptance of pesticide use and biotechnology in agriculture

Protecting crops from infestations is critical to ensuring stable, safe food production. However, many consumers are concerned about the use of pesticides and agricultural biotechnology (agri-biotech) applications. A lack of consumer acceptance can prevent potentially beneficial applications from being utilized. This study examines consumer acceptance of pesticide use in conventional and organic agriculture and agri-biotech applications as crop-protection measures. An online between-subject experiment was conducted with participants from the German-speaking part of Switzerland (N = 643). The results revealed that consumers were most willing to accept gene transfers as a protection measure, provided the gene came from a wild variety of the same species as the cultivated plant. Both chemophobia and the importance of naturalness in food influence consumer acceptance of pesticide use and agri-biotech applications. Addressing chemophobia and informing consumers about the role of technologies in pest-management and crop-protection could lead them to trust and accept related agricultural policies.     

Application of a qualitative and quantitative real-time polymerase chain reaction method for detecting genetically modified papaya line 55-1 in papaya products

Genetically modified (GM) papaya (Carica papaya L.) line 55-1 (55-1), which is resistant to papaya ringspot virus infection, has been marketed internationally. Many countries have mandatory labeling regulations for GM foods, and there is a need for specific methods for detecting 55-1. Here, an event- and construct-specific real-time polymerase chain reaction (PCR) method was developed for detecting 55-1 in papaya products. Quantitative detection was possible for fresh papaya fruit up to dilutions of 0.001% and 0.01% (weight per weight [w/w]) for homozygous SunUp and heterozygous Rainbow cultivars, respectively, in non-GM papaya. The limit of detection and quantification was as low as 250 copies of the haploid genome according to a standard reference plasmid. The method was applicable to qualitative detection of 55-1 in eight types of processed products (canned papaya, pickled papaya, dried fruit, papaya-leaf tea, jam, puree, juice, and frozen dessert) containing papaya as a main ingredient.     

Recent trends in detecting,controlling, and detoxifying of patulin mycotoxin using biotechnology methods

Patulin (PAT) is a mycotoxin that can contaminate many foods and especially fruits and fruit‐based products. Therefore, accurate and effective testing is necessary to enable producers to comply with regulations and promote food safety. Traditional approaches involving the use of chemical compounds or physical treatments in food have provided practical methods that have been used to date. However, growing concerns about environmental and health problems associated with these approaches call for new alternatives. In contrast, recent advances in biotechnology have revolutionized the understanding of living organisms and brought more effective biological tools. This review, therefore, focuses on the study of biotechnology approaches for the detection, control, and mitigation of PAT in food. Future aspects of biotechnology development to overcome the food safety problem posed by PAT were also examined. We find that biotechnology advances offer novel, more effective, and environmental friendly approaches for the control and elimination of PAT in food compared to traditional methods. Biosensors represent the future of PAT detection and use biological tools such as aptamer, enzyme, and antibody. PAT prevention strategies include microbial biocontrol, the use of antifungal biomolecules, and the use of microorganisms in combination with antifungal molecules. PAT detoxification aims at the breakdown and removal of PAT in food by using enzymes, microorganisms, and various adsorbent biopolymers. Finally, biotechnology advances will be dependent on the understanding of fundamental biology of living organisms regarding PAT synthesis and resistance mechanisms.     

Nutritional and Safety Assessments of Foods and Feeds Nutritionally Improved through Biotechnology: An Executive Summary

The global demand for food is increasing because of the growing world population. At the same time, availability of arable land is shrinking. Traditional plant breeding methods have made and will continue to make important contributions toward meeting the need for more food. In many areas of the world, however, the problem is food quality. There may be enough energy available from food, but the staple foods lack certain essential nutrients. In the developed world, demand for "functional foods" (that is, foods that provide health benefits beyond basic nutrition) is increasing. Nutritional improvements in foods could help to meet both of these demands for improved food quality. Modern agricultural biotechnology, which involves the application of cellular and molecular techniques to transfer DNA that encodes a desired trait to food and feed crops, is proving to be a powerful complement to traditional methods to meet global food requirements. An important aspect of biotechnology is that it provides access to a broad array of traits that can help meet this need for nutritionally improved cultivars. The new varieties developed through modern biotechnology have been identified by a number of terms, including genetically modified (GM or GMO), genetically engineered (GE or GEO), transgenic, biotech, recombinant, and plants with novel traits (PNTs). For the present discussion, the term "GM" will be used because of its simplicity and broad public recognition.     

Opportunities for biotechnology and policy regarding mycotoxin issues in international trade

Despite being introduced more than a decade ago, agricultural biotechnology still remains framed in controversy impacting both the global economy and international regulations. Controversies surrounding agricultural biotechnology produced crops and foods commonly focus on human and environmental safety, intellectual property rights, consumer choice, ethics, food security, poverty reduction and environmental conservation. Originally, some consumers were reluctant to accept the first generation agricultural biotechnology products because they appeared to primarily benefit agricultural producers; however, it is clear from continued evaluations that these technologies also improved both the safety and wholesomeness of food and helped improve the environment. Plants engineered to resist insect pests and tolerate less toxic pesticides resulted in improved yields thereby enabling farmers to produce more food per acre while reducing the need for herbicides, pesticides, and water and tilling. An indirect benefit of reduced pest damage in transgenic corn expressing genes to control insect pests is lower levels of mycotoxins, most notably those caused by the genus Fusarium. Mycotoxins are an important regulatory issue globally because of their toxic and carcinogenic potential to humans and animals. Complicating this issue is the fact that toxicological databases for mycotoxins are relatively incomplete compared to other food contaminants. Current debates about agricultural biotechnology and mycotoxins reveal significant differences in perception of associated risks and benefits. When faced with uncertainty, regulators tend to set limits as low as possible. Additionally, some regulators invoke the "Precautionary Principle" when limited information is available or disputes over interpretation exist for possible contaminants, including mycotoxins. A major concern regarding use of the "Precautionary Principle" is the appearance that regulators can justify setting any limit on the basis of inconclusive or unknown potential hazards of a contaminant which may significantly impact global trade because mycotoxin residues vary widely between countries. This paper describes the current economic and heath impact of these regulations and their impact on international trade.     

农作物和食品中链格孢毒素污染及其脱毒方法研究进展

链格孢菌是多种重要农作物的病原体,可产生70余种链格孢毒素,不仅造成农作物减产和品质下降,也会存在于食品加工制品中,对人类和动物造成安全威胁。链格孢毒素可污染粮食、水果和蔬菜等农作物,在番茄及其产品、小麦和果干等食品中的含量较高,尤其以细交链孢菌酮酸的含量最高。脱除链格孢毒素的方法主要包括物理法、化学法和微生物法,通过降解、吸附毒素或者抑制真菌产毒以降低农作物或食品中链格孢毒素的含量。本文总结了农作物和食品中链格孢毒素污染现状及其脱毒方法,旨在为降低链格孢菌毒素对农作物的危害,提高食品安全提供参考。     

A histochemical method using a substrate of beta-glucuronidase for detection of genetically modified papaya

A histochemical assay for detecting genetically modified (GM) papaya (derived from Line 55-1) is described. GM papaya, currently undergoing a safety assessment in Japan, was developed using a construct that included a beta-glucuronidase (GUS) reporter gene linked to a virus coat protein (CP) gene. Histochemical assay was used to visualize the blue GUS reaction product from transgenic seed embryos. Twelve embryos per fruit were extracted from the papaya seeds using a surgical knife. The embryos were incubated with the substrate 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-Gluc) in a 96-well microtiter plate for 10-15 hours at 37 degrees C. Seventy-five percent of GM papaya embryos should turn blue theoretically. The histochemical assay results were completely consistent with those from a qualitative polymerase chain reaction (PCR) method developed by this laboratory. Furthermore, the method was validated in a five-laboratory study. The method for detection of GM papaya is rapid and simple, and does not require use of specialized equipment.     

番木瓜加工副产物综合利用研究进展

番木瓜是番木瓜科番木瓜属多年生肉质草本植物,具有较高的营养价值和药用价值。其含有丰富的糖类、多酚、番木瓜碱,有机酸等物质,具有抗氧化、降血糖及抑菌等多种功效,用途甚广。番木瓜皮、籽、叶具有多种活性物质,副产物加工具有巨大的经济效益。但目前木瓜副产品较少,利用率较低,造成极大的浪费。本综述整理番木瓜加工过程产生的副产物及其功能活性成分在食品工业中的应用,以期对番木瓜副产物合理应用,减少环境污染提供科学指导。     

Cheese Manufacture Assisted by High Pressure

The processing of foods by high pressure is gaining commercial acceptance. Various food products processed by high pressure are now available in stores and the list of commercialized products is expected to expand as new applications are developed. Currently, industrial applications within the dairy industry are being sought. This article describes what high pressure processing is, presents some of the changes experienced by milk constituents and how such changes are reflected in final products, and presents some of the proposed applications for milk cheese or cheese processing.