File Name: food packaging and shelf life .zip
Nano packaging is currently one of the most important topics in food packaging technologies. The aim of the application of this technology in food packaging is increasing shelf life of foods by preventing internal and external corruption and microbial contaminations. Use of silver nanoparticles in food packaging has recently attracted much attention. The aim of this study was to investigate the effect of nano-silver packaging in increasing the shelf life packages of nuts in an In vitro model. In this experimental study, the effects of different nano-silver concentrations 0, 1, 2 and 3 percent on biological and chemical properties of samples of nuts including walnuts, hazelnuts, almonds and pistachios were evaluated during 0, 3, 6, 9, 12, 15, 18, 21 and 24 months.
To investigate the effects of packaging on the quality aspects of radish, Korean radish roots Raphanus sativus L. Lower color difference values were also found in this treatment.
Both film packaged samples had lower scores of black spot, surface shrinkage, and fungal infection incidence which revealed significantly longer marketable periods. HDPE film packaged samples exhibited longer shelf life more than one and two months compared to control and unpacked samples, respectively.
Results suggest that HDPE film packaging can extend postharvest life of radish while curing might have little but beneficial effects in maintaining the quality characteristics. To our knowledge, this is the first report on quality evaluation of Korean radish during an extended storage period simulating the Korean industrial practices. Among the root vegetables, radish Raphanus sativus L.
Like many other vegetables, radishes are low in calories and sugar and high in fiber content which make them an excellent choice for everyday diet. Being a member of Brassicaceae family, radish helps in decreasing the risk of many chronic, life-threatening illnesses, including heart disease, diabetes, and colon cancer [ 1 ]. Hence, radish was suggested as an alternative treatment for various ailments including hyperlipidemia, coronary heart diseases, and cancer [ 2 ].
Due to the diversity of production and adaptation, numerous varieties of radishes are grown worldwide almost throughout the year under varying climatic conditions. Korean radishes are larger than most common radishes. They have a crisp, firm flesh that offers a relatively mild radish flavor and spicy taste. Its thick, smooth skin is creamy white and capped with pale green shoulders whereas the flesh is white with a texture and taste similar to that of the daikon radish. Unlike the carrot shaped daikon, however, the Korean radish is rounded and plump with an oblong shape.
Kang et al. Moreover, radish roots cultivated in the spring showed softer root firmness and shorter postharvest life compared to those produced in the fall. Being an essential part of numerous Korean dishes, the year round availability of radish is needed to ensure the continued supply to the domestic consumers. Therefore, storage of radish at least for a certain period is an obvious and common practice for distribution centers, suppliers, or industries involved in producing processed or fermented food made from radish such as kimchi.
However, radishes are carelessly handled during postharvest stages possibly due to its bulk volume, greater utilization for processing, and lesser uses fresh compared to other fruits and vegetables. As a result, both the physical and nutritional qualities of radishes deteriorate during storage that contributes largely to purchasing decision of the consumers. In terms of consumer preference, root color is one of the main quality characteristics of radish and is regarded as an indicator of radish quality [ 4 ].
A near perfect visual appearance is a common expectation of the consumers for buying fresh commodities. In case of Korean radish, the whiteness of the root is regarded as one of the pivotal factors in determining the freshness by which consumers can easily judge the produce for buying decision. Moreover, higher surface areas as their voluminous property make them more prone to dehydration.
Other quality parameters include firmness, total soluble solids, total acidity, and hydrogenic potential [ 6 ]. Quality determining factors like freshness or appearance and color of fresh commodities change during storage, handling, and display and are greatly influenced by the pre- and postharvest factors such as cultivation period, developmental stages, and postharvest conditions [ 7 — 9 ]. A number of physical, chemical, and biological methods have been utilized at postharvest stages in order to maintain or improve the quality of fresh commodities leading to extending their shelf life [ 10 — 12 ].
Different postharvest treatments such as packaging influence primary and secondary compounds in fruits and vegetables. Packaging, for instance, not only is considered as a food container that prevents mechanical damage and ensures hygiene, but also acts as a useful tool for extending storage life [ 13 , 14 ], maintaining bioactive substances [ 10 , 15 ] and flavor related volatile compounds [ 16 ]. Curing is also a physical technique applied for several commodities after harvest to dry the outer skins, roots, and other tissues which make them more resistant to disease causing organisms [ 17 , 18 ].
Controlling storage temperature, on the other hand, is a crucial factors for maintaining physicochemical and other quality attributes of numerous fresh vegetables. Although a number of researches have been conducted on radish roots focusing on the potential uses as minimally processed ready-to-use or fresh-cut produces [ 6 , 19 , 22 ] and as an ingredient of fermented or processed foods [ 23 , 24 ], findings relating to the maintenance of freshness and quality of whole radish roots during storage are very limited.
Korean radish roots Raphanus sativus L. Kwandong grown in an open commercial field in Yongam, Jeonnam area of Jeollanam province, Republic of Korea, during spring season were used in this study. After reaching the laboratory, roots were carefully sorted, excess soil or dust if any was removed by using paper towel, and deformed, damaged, or physically injured radish roots were discarded.
Then the attached leaf portions were trimmed from each radish to reduce the surface area that may cause more evaporation loss during storage. About 10 radish roots were accommodated in a paper cartoon box or plastic crates, used as a single replication. After packing radishes in the films, they were lightly closed and placed inside the plastic crates which were then arranged in a palate that contained a maximum of four layers of plastic crates.
After each packaging treatment, whole radish boxes or crates were weighed and marked to estimate the loss of weight on the evaluation day during storage. This temperature was chosen as a recommended storage temperature for radish roots [ 21 ]. Quality evaluations were carried out on 0, 30, 60, 90, , and days of storage.
The individual radish boxes or crates were weighed on the day of packaging and considered as initial fresh weight. To avoid water condensation on the surface of roots that might affect fresh weight, we conducted weight measurement on each evaluation day inside the storage room. However, consumers evaluate the freshness of radish based on the color of white part and therefore we measured color parameters only from the white portion, just beneath the green portion.
A chromameter Minolta CR, Minolta, Osaka, Japan was used to record color readings from the opposite equatorial sites on each of ten roots in a replication which yielded an average value from a total of 60 readings from each treatment on each measurement day.
Changes of color of radish roots were quantified in the , , and color space. The numerical color values of , , and were used to estimate whiteness index WI [ 25 ] see 2 , total color difference [ 22 ] see 3 , and chroma [ 22 ] see 4. Puncture force was measured from five randomly chosen radish roots from each replication on each evaluation day.
For skin puncture test measurement, the lower portion of radish roots was vertically divided into two parts and then a puncture hole was made on the middle of the skin of each divided portion. Three readings were taken from the inner tissues of each radish slice that resulted in 15 pieces of data to get the average of flesh puncture force, whereas 10 reading were taken from skin portion calculated as average skin puncture force from each replication.
After texture measurement, the remaining five radish roots in a replication were used for TSS and pH measurement. Then the slices were separately shredded to make small pieces, wrapped with 2 layers of cotton cloth, and placed in a juice maker attached to an air supplier Fru-X80, GooJung Chromatech Inc. Then pressure was created by the air supplier to obtain a homogenized solution of radish roots sample.
Five measurements were conducted from five radish roots in a replication and the values were averaged. The sensory analysis of radish roots was performed by an 8-member 5 men and 3 women, aged 28—52 expert panel on each evaluation day at room temperature.
Before starting the experiment, the members of the panel were trained to recognize and score black spot incidence, fungal attack incidence, decay index, and overall visual quality of radish roots by adopting them from another similar previously conducted experiment. After measuring the fresh weight of radish inside the storage room, samples of different treatments were moved to room temperature and washed thoroughly in running tap water, and the roots were then placed on the table over a layer of paper towel.
The excess water remaining on the surface of the roots was also absorbed with clean paper towel. Overall visual quality of a sample was referred to as acceptability or marketability and a score of 5 was considered as the limit of marketability. Decay index was then calculated separately for each replication by the following formula:. The experiment was conducted with three replications per treatment per evaluation period.
The percentages of relative fresh weight of radish roots under different packaging treatments during storage are presented in Figure 3. Substantial amount of water losses was recorded in the samples which were not packaged with HDPE films while the minimum losses were observed for film packaged samples. Control sample, on the other hand, showed intermediate water loss trend in between the amount of water loss of film packaged and nonpackaged samples throughout the storage.
This result clearly indicated the beneficial effect of using packaging film in maintaining fresh weight of radish during long term storage. At the end of the storage, we recorded only 2. However, due to the presence of micro holes in the film, we did not observe water accumulation inside the packages which protected against decay or damage of the sample.
Consequently, all the samples without packaging with HDPE film lost their marketability before 90 days of storage later discussion. Maintaining freshness by retaining fresh weight of fresh commodities is one of the most critical challenges that face the supplier, processing centers, industries, whole sellers, or even retailers. Since curing is a common practice for drying the outer skins of many underground vegetables like onion which helps in reducing water loss and entry of pathogen during storage [ 12 ], we found slightly higher relative fresh weight in both the cured samples than the uncured samples of similar treatments.
However, we observed negligible water loss about 0. Although curing is usually practiced in higher temperature than room temperature, our objective of curing was to make a protective layer on root surface without hampering the freshness and quality. Moreover, we used moving electric fan to cool down the root surface temperature as an act similar to precooling operation of harvested commodities.
Due to the voluminous nature of Korean radish, many industries practice storing radish in large sized bag or container without any packaging film. To simulate such open storage practices, we stored radishes in plastic crates only with or without curing which depicted higher water loss resulting in shriveling Figure 2 e and deterioration of visual quality from the beginning of storage. Tsouvaltzis and Brecht [ 20 ] observed about 1. However, Ayub et al.
Again, del Aguila et al. It seems that storage temperature greatly affects the fresh weight retention ability of radishes as observed in many other vegetables especially in leafy vegetables.
It is also likely that different researchers used different kinds or varieties of radishes which might have shown varying pattern of postharvest behavior as radish grows in almost every part of the world due to its broad adaptation to climatic condition [ 4 ]. The film used to package radish roots in this study significantly retarded fresh weight loss of roots during storage compared to control and unpackaged sample.
The effectiveness of packaging film for maintaining fresh weight and other quality factors in radish has also been observed in previous study [ 11 ]. The color parameters of radish roots measured on each evaluation day are presented in Figure 4. Since surface color is the first and most critical quality parameter judged by the consumer at the time of purchase, different color indices may require getting detailed characterization of the quality attributes of fresh commodities or food [ 22 ].
Although the values of reflect the lightness or whiteness of a produce, we separately calculated the whiteness index WI to get a clear understanding about the whiteness of roots as the white portion was used to investigate the color quality of roots.
However, we found almost similar pattern of changes of and WI values throughout the storage Figures 4 a and 4 b. Similar to weight loss data, unpacked radish roots showed rapid deterioration of color parameters while a gradual and slower decline of and WI values was found in control sample.
Although whiteness or lightness quality of both HDPE packaged samples was insignificantly different from those of control sample until days of storage, it was significantly different from those of unpacked samples. However, only cured sample packaged in film showed insignificant but higher and WI values until days of storage among the treatments which became significantly higher at the last evaluation day Figures 4 a and 4 b. This treatment also showed nearly similar values of and WI until 60 days of storage and therefore received the highest visual quality scores later discussion among the treatments.
This implies that color changes of whole radish root are more insensitive to that of leaf or leafy vegetables and well documented by Tsouvaltzis and Brecht [ 20 ]. Therefore, many food industries which use radish root as one of the food ingredients store radish carelessly at lower temperature, especially in Korea.
However, the scientific reports on radish root storage for extended periods are also limited which encouraged us to conduct this study.
The decreases in and WI values indicated the changes of white color of root to yellowish or lighter brown color when storage time elapses. Goyeneche et al. Although the insignificant changes of radish root color during storage at 5C or 10C for 9 days were reported [ 20 ], our results were different from theirs obviously because of the storage period, condition, and variety used for this study.
Since chroma represents color saturation which varies from dull low value to vivid color high value and reflects the intensity or strength of hue, we calculated chroma in order to well describe the real changes of radish root color.
The chroma values also increased during storage and followed nearly similar patterns as observed for values Figure 4 d.
Fresh products are characterized by reduced shelf-life because they are an excellent growth medium for a lot of microorganisms. Therefore, the microbial spoilage causing significant food supply losses has become an enormous economic and ethical problem worldwide. The antimicrobial packaging is offering a viable solution to tackle this economic and safety issue by extending the shelf-life and improving the quality and safety of fresh products. The goal of this study was to investigate the effects of a food contact surface of polyethylene terephthalate PET functionalized with the previously characterized antimicrobial peptide mitochondrial-targeted peptide 1 MTP1 , in reducing the microbial population related to spoilage and in providing the shelf-life stability of different types of fresh foods such as ricotta cheese and buffalo meat. Modified polymers were characterized concerning the procedure of plasma-activation by water contact angle measurements and Fourier transform infrared spectroscopy measurements in attenuated total reflection mode ATR-FTIR. Results showed that the MTP1-PETs provided a strong antimicrobial effect for spoilage microorganisms with no cytotoxicity on a human colon cancer cell line.
and interlinked, with food packaging is the concept of shelf life - the length of The system converts your article files to a single PDF file used in.
Once production of your article has started, you can track the status of your article via Track Your Accepted Article. Help expand a public dataset of research that support the SDGs. Food packaging plays a vital role in preserving food throughout the distribution chain. Without packaging, the processing of food can become compromised as it is contaminated by direct contact with physical, chemical, and biological contaminants. In recent years, the development of novel food packaging Directly related, and interlinked, with food packaging is the concept of shelf life - the length of time that foods, beverages, pharmaceutical drugs, chemicals, and many other perishable items are given before they are considered unsuitable for sale, use, or consumption. Food Packaging and Shelf Life caters to the needs of scientists, material scientists, food chemists and microbiologists in the area of food packaging and shelf life.
USA info metergroup. Why do shelf-life testing? Insufficient packaging allows water activity in food products to rise or fall over time—causing undesirable physical changes, moisture migration, chemical degradation, and susceptibility to microbial growth. Over-packaging, on the other hand, is expensive and can erode profits.
To investigate the effects of packaging on the quality aspects of radish, Korean radish roots Raphanus sativus L. Lower color difference values were also found in this treatment. Both film packaged samples had lower scores of black spot, surface shrinkage, and fungal infection incidence which revealed significantly longer marketable periods. HDPE film packaged samples exhibited longer shelf life more than one and two months compared to control and unpacked samples, respectively. Results suggest that HDPE film packaging can extend postharvest life of radish while curing might have little but beneficial effects in maintaining the quality characteristics.
Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. It applies to cosmetics , foods and beverages , medical devices , medicines , explosives , pharmaceutical drugs , chemicals , tyres , batteries , and many other perishable items. In some regions, an advisory best before , mandatory use by or freshness date is required on packaged perishable foods. The concept of expiration date is related but legally distinct in some jurisdictions. Shelf life is the recommended maximum time for which products or fresh harvested produce can be stored, during which the defined quality of a specified proportion of the goods remains acceptable under expected or specified conditions of distribution, storage and display. If the cans look okay, they are safe to use.
Before submission check for plagiarism via Turnitin. Typeset is a very innovative solution to the formatting problem and existing providers, such as Mendeley or Word did not really evolve in recent years. Guideline source: View. All company, product and service names used in this website are for identification purposes only.
Компьютерное время, необходимое для их угадывания, растягивалось на месяцы и в конце концов - на годы. К началу 1990-х годов ключи имели уже более пятидесяти знаков, в них начали использовать весь алфавит АСКИ - Американского национального стандартного кода для обмена информацией, состоящего из букв, цифр и символов. Число возможных комбинаций приблизилось к 10 в 120-й степени - то есть к единице со 120 нулями.
- Стратмор выдержал паузу. - Какой была твоя первая реакция, когда я сообщил тебе о смерти Танкадо. Сьюзан нахмурилась.
Это была шутка, Мидж. - Но он знал, что сказанного не вернешь. ГЛАВА 62 Коммандер и Сьюзан стояли у закрытого люка и обсуждали, что делать. - Итак, внизу у нас погибший Чатрукьян, - констатировал Стратмор.
Он писал алгоритмы и зарабатывал неплохие деньги.
Your email address will not be published. Required fields are marked *