Abstract: The objective of the research was to evaluate the
quality of milk pomade sweet – sherbet packed in different packaging
materials (Multibarrier 60, met.BOPET/PE, Aluthen), by several
packaging technologies – active and modified atmosphere (MAP)
(consisting of 100% CO2), and control – in air ambiance.
Experiments were carried out at the Faculty of Food Technology of
Latvia University of Agriculture. Samples were stored at the room
temperature +21±1 °C. The physiochemical properties – weight
losses, moisture, hardening, colour and changes in headspace
atmosphere concentration (CO2 and O2) of packs were analysed
before packaging and after 2, 4, 6, 8, 10 and 12 storage weeks.
Abstract: Langmuir–Blodgett (LB) films of polyaniline (PANI) grown onto ITO coated glass substrates were utilized for the fabrication of Uric acid biosensor for efficient detection of uric acid by immobilizing Uricase via EDC–NHS coupling. The modified electrodes were characterized by atomic force microscopy (AFM). The response characteristics after immobilization of uricase were studied using cyclic voltammetry and electrochemical impedance spectroscopy techniques. The uricase/PANI/ITO/glass bioelectrode studied by CV and EIS techniques revealed detection of uric acid in a wide range of 0.05 mM to 1.0 mM, covering the physiological range in blood. A low Michaelis–Menten constant (Km) of 0.21 mM indicates the higher affinity of immobilized Uricase towards its analyte (uric acid). The fabricated uric acid biosensor based on PANI LB films exhibits excellent sensitivity of 0.21 mA/mM with a response time of 4 s, good reproducibility, long shelf life (8 weeks) and high selectivity.
Abstract: The shelf life of fish was extended using disinfection
properties of ozone. For this purpose, Trout specimens were exposed
to ozone in the aqueous media for two hours and their microbial
growth and biochemical properties were measured over time.
Microbial growth of ozone treated fish was significantly slower than
control sample, resulting in lower counts of bacteria. According to
the biochemical tests; ozone treatment had no negative effects on fat,
protein and humidity of fish. Peroxide and TVN (Total Volatile
Nitrogen) measurements showed that treatment by ozone increased
the trout shelf life from 4 days to 6 days. According to the sensory
analysis, no changes were observed in color or flavor of the ozone
treated trout.
Abstract: This paper presents a cold chain monitoring system which focuses on assessment of quality and dynamic pricing information about food in cold chain. Cold chain is composed of many actors and stages; however it can be seen as a single entity since a breakdown in temperature control at any stage can impact the final quality of the product. In a cold chain, the shelf life, quality, and safety of perishable food throughout the supply chain is greatly impacted by environmental factors especially temperature. In this paper, a prototype application is implemented to retrieve timetemperature history, the current quality and the dynamic price setting according to changing quality impacted by temperature fluctuations in real-time.
Abstract: The effects of seawater and slurry ice bleeding methods on the sensory, microbiological and chemical quality changes of cod fillets during chilled storage were examined in this study. The results from sensory evaluation showed that slurry ice bleeding method prolonged the shelf life of cod fillets up to 13-14 days compared to 10-11 days for fish bled in seawater. Slurry ice bleeding method also led to a slower microbial growth and biochemical developments, resulting lower total plate count (TPC), H2S-producing bacteria count, total volatile basic nitrogen (TVB-N), trimethylamine (TMA), free fatty acid (FFA) content and higher phospholipid content (PL) compared to those of samples bled in seawater. The results of principle component analysis revealed that TPC, H2S-producing bacteria, TVB-N, TMA and FFA were in significant correlation. They were also in negative correlation with sensory evaluation (Torry score), PL and water holding capacity (WHC).
Abstract: Experiments have been carried out at the Latvia
University of Agriculture Department of Food Technology. The aim
of this work was to assess the effect of sous vide packaging during
the storage time of salad with meat in mayonnaise at different storage
temperature. Samples were evaluated at 0, 1, 3, 7, 10, 15, 18, 25, 29,
42, and 52 storage days at the storage temperature of +4±0.5 ºC and
+10±0.5 ºC. Experimentally the quality of the salad with meat in
mayonnaise was characterized by measuring colour, pH and
microbiological properties. The sous vide packaging was effective in
protecting the product from physical, chemical, and microbial quality
degradation. The sous vide packaging significantly reduces microbial
growth at storage temperature of +4±0.5 ºC and +10±0.5 ºC.
Moreover, it is possible to extend the product shelf life to 52 days
even when stored at +10±0.5 ºC.
Abstract: Tomato powder has good potential as substitute of tomato paste and other tomato products. In order to protect physicochemical properties and nutritional quality of tomato during dehydration process, investigation was carried out using different drying methods and pretreatments. Solar drier and continuous conveyor (tunnel) drier were used for dehydration where as calcium chloride (CaCl2), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl2 +KMS), and sodium chloride (NaCl) selected for treatment.. lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning in addition to moisture, sugar and titrable acidity were studied. Results show that pre-treatment with CaCl2 and NaCl increased water removal and moisture mobility in tomato slices during drying of tomatoes. Where CaCl2 used along with KMS the NEB was recorded the least compared to other treatments and the best results were obtained while using the two chemicals in combination form. Storage studies in LDPE polymeric and metalized polyesters films showed less changes in the products packed in metallized polyester pouches and even after 6 months lycopene content did not decrease more than 20% as compared to the control sample and provide extension of shelf life in acceptable condition for 6 months. In most of the quality characteristics tunnel drier samples presented better values in comparison to solar drier.
Abstract: Experiments were carried out at the Faculty of Food
Technology of Latvia University of Agriculture (LLU). Soft cheese
Kleo produced in Latvia was packed in a biodegradable PLA without
barrierproperties and VC999 BioPack lidding film PLA, coated with
a barrier of pure silicon oxide (SiOx) and in combination with
modified atmosphere (MAP) the influence on the shelf life was
investigated and compared with some conventional (OPP, PE/PA,
PE/OPA and Multibarrier 60) polymer film impact. Modified
atmosphere consisted of carbon dioxide CO2 (E 290) 30% and
nitrogen N2 (E 941) 70%. The analyzable samples were stored at the
temperature of +4.0±0.5 °C up to 32 days- and analyzed before
packaging and in the 0, 5th, 11th, 15th, 18th, 22nd, 25th, 29th and 32nd
day of storage. The shelf life was extended along to 32 days, good
outside appearance and lactic acid aroma was observed.
Abstract: Processing tabah bamboo shoot as fermented pickle is
one of the way to increase the shelf life of this bamboo shoot. The
advantage of this shoot is low concentration of hydro cyanic acid
(HCN) make it potential for functional food product. This study
aimed to determine the characteristic of tabah bamboo shoot pickle
such as total of lactic acid bacteria (LAB), pH, total acidity, and
hydro cyanic acid (HCN) content, and also find the LAB’s type
involved during fermentation, and organic acids’ profiles. The pickle
was made by natural fermentation with 6% salt concentration and
fermentation conducted for 13 days.
The result showed during the fermentation time, in the 4th day
LAB’s number was highest as much as 72 x 107 CFU/ml and the
lowest pH was 3.09. We also found decreasing in HCN from 37.8
ppm at the beginning to 20.52 ppm at the end of fermentation
process. The organic acids detected during the fermentation were
lactic acid with the highest concentration was 0.0546 g/100 g and
small amount of acetic acid. By using PCR method, the 18 of LABs
which had rod shape were detected as member of Lactobacillus spp.,
in which 17 strains detected as L. plantarum.
Abstract: The objective of the research was to evaluate the
hardness stability of milk pomade sweets packed in several
packaging materials (OPP, Multibarrier 60 HFP, BIALON 65
HFP, BIALON 50 HFP, ECOLEAN) by several packaging
technologies – modified atmosphere (MAP) (consisting of
30% CO2+70% N2; 30% N2+70% CO2 and 100% CO2) and
control – in air ambiance. Samples were stored at the room
temperature +21±1 °C. The studies of the samples were
carried out before packaging and after 2, 4, 6, 8, and 10
storage weeks.
Abstract: This study investigated the use of modified
atmosphere packaging (MAP) and different packaging to extend the
shelf life of Barbari flat bread. Three atmospheres including 70%CO2
and 30%N2, 50% CO2 and 50%N2 and a normal air as control were
used. The bread samples were packaged in three type pouches. The
shelf life was determined by appearance of mold and yeast (M +Y) in
Barbari bread samples stored at 25 ± 1°C and 38 ± 2% relative
humidity. The results showed that it is possible to prolong the shelf
life of Barbari bread from four days to about 21 days by using
modified atmosphere packaging with high carbon dioxide
concentration and high-barrier laminated and vacuum bags packages.
However, the hardness of samples kept in MAP increase significantly
by increase of carbon dioxide concentration. The correlation
coefficient (r) between headspace CO2 concentration and hardness
was 0.997, 0.997 and 0.599 for A, B and C packaging respectively.
High negative correlation coefficients were found between the crumb
moisture and the hardness values in various packaging. There were
significant negative correlation coefficients between sensory
parameters and hardness of texture.
Abstract: Tomato powder has good potential as substitute of tomato paste and other tomato products. In order to protect physicochemical properties and nutritional quality of tomato during dehydration process, investigation was carried out using different drying methods and pretreatments. Solar drier and continuous conveyor (tunnel) drier were used for dehydration where as calcium chloride (CaCl2), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl2 +KMS), and sodium chloride (NaCl) selected for treatment.. lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning in addition to moisture, sugar and titrable acidity were studied. Results show that pre-treatment with CaCl2 and NaCl increased water removal and moisture mobility in tomato slices during drying of tomatoes. Where CaCl2 used along with KMS the NEB was recorded the least compared to other treatments and the best results were obtained while using the two chemicals in combination form. Storage studies in LDPE polymeric and metalized polyesters films showed less changes in the products packed in metallized polyester pouches and even after 6 months lycopene content did not decrease more than 20% as compared to the control sample and provide extension of shelf life in acceptable condition for 6 months. In most of the quality characteristics tunnel drier samples presented better values in comparison to solar drier.
Abstract: The quality and shelf life of foods of containing lipids (fats and oils) significantly reduces due to rancidity.Applications of natural antioxidants are one of the most effective manners to prevent the oxidation of oils and lipids. The antioxidant properties of juice extracted from barberry fruit (Berberris vulgaris.L) using maceration and SWE (10 bars and 120 - 180°C) methods were investigated and compared with conventional method. The amount of phenolic compound and reduction power of all samples were determined and the data were statistically analyzed using multifactor design. The results showed that the total amount of phenolic compound increased with increasing of pressure and temprature from 1861.9 to 2439.1 (mg Gallic acid /100gr Dry matter). The ability of reduction power of SWE obtained antioxidant extract compared with BHA (synthetic antioxidant) and ascorbic acid (natural antioxidant). There were significant differences among reduction power of extracts and there were remarkable difference with BHA and Ascorbic acid (P
Abstract: Experiments have been carried out at the Latvia
University of Agriculture Department of Food Technology. The aim
of this work was to assess the effect of thermal treatment in flexible
retort pouch packaging on the quality of potatoes’ produce during the
storage time. Samples were evaluated immediately after retort
thermal treatment; and following 1; 2; 3 and 4 storage months at the
ambient temperature of +18±2ºC in vacuum packaging from
polyamide/polyethylene (PA/PE) and aluminum/polyethylene
(Al/PE) film pouches with barrier properties. Experimentally the
quality of the potatoes’ produce in dry butter and mushroom
dressings was characterized by measuring pH, hardness, color,
microbiological properties and sensory evaluation. The sterilization
was effective in protecting the produce from physical, chemical, and
microbial quality degradation. According to the study of obtained
data, it can be argued that the selected product processing technology
and packaging materials could be applied to provide the safety and
security during four-month storage period.
Abstract: The research object was wheat bread. Experiments
were carried out at the Faculty of Food Technology of the Latvia
University of Agriculture. An active packaging in combination with
modified atmosphere (MAP, CO2 60% and N2 40%) was examined
and compared with traditional packaging in air ambiance. Polymer
Multibarrier 60, PP and OPP bags were used. Influence of iron based
oxygen absorber in sachets of 100 cc obtained from Mitsubishi Gas
Chemical Europe Ageless® was tested on the quality during the shelf
of wheat bread. Samples of 40±4 g were packaged in polymer
pouches (110 mm x 120 mm), hermetically sealed by MULTIVAC
C300 vacuum chamber machine, and stored in room temperature
+21.0±0.5 °C. The physiochemical properties – weight losses,
moisture content, hardness, pH, colour, changes of atmosphere
content (CO2 and O2) in headspace of packs, and microbial
conditions were analysed before packaging and in the 7th, 14th, 21st
and 28th days of storage.
Abstract: White scar oyster (Crassostrea belcheri) is often eaten
raw and being the leading vehicle for foodborne disease, especially
Salmonella Weltevreden which exposed the prominent and most
resistant to radiation. Gamma irradiation at a low dose of 1 kGy was
enough to eliminate S. Weltevreden contaminated in oyster meat at a
level up to 5 log CFU/g while it still retain the raw characteristics and
equivalent sensory quality as the non-irradiated one. Process
development of ready-to-eat chilled oyster meat was conducted by
shucking the meat, individually packed in plastic bags, subjected to 1
kGy gamma radiation at chilled condition and then stored in 4oC
refrigerated temperature. Microbiological determination showed the
absence of S. Weltevreden (5 log CFU/g initial inoculated) along the
whole storage time of 30 days. Sensory evaluation indicated the
decreasing in sensory scores along storage time which determining
the product shelf life to be 18 days compared to 15 days of nonirradiated
one. The most advantage of developed process was to
provide the safe raw oyster to consumers and in addition sensory
quality retained and 3-day extension shelf life also exist.
Abstract: Microwave energy is a superior alternative to several other thermal treatments. Extraction techniques are widely employed for the isolation of bioactive compounds and vegetable oils from oil seeds. Among the different and new available techniques, microwave pretreatment of seeds is a simple and desirable method for production of high quality vegetable oils. Microwave pretreatment for oil extraction has many advantages as follow: improving oil extraction yield and quality, direct extraction capability, lower energy consumption, faster processing time and reduced solvent levels compared with conventional methods. It allows also for better retention and availability of desirable nutraceuticals, such as phytosterols and tocopherols, canolol and phenolic compounds in the extracted oil such as rapeseed oil. This can be a new step to produce nutritional vegetable oils with improved shelf life because of high antioxidant content.
Abstract: Experiments with pumpkin-rowanberry marmalade
candies were carried out at the Faculty of Food Technology of the
Latvia University of Agriculture. The objective of this investigation
was to evaluate the quality changes of pumpkin-rowanberry
marmalade candies packed in different packaging materials during
the storage of 15 weeks, and to find the most suitable packaging
material for prolongation of low sugar marmalade candies shelf-life.
An active packaging in combination with modified atmosphere
(MAP, CO2 100%) was examined and compared with traditional
packaging in air ambiance. Polymer Multibarrier 60 and paper bags
were used. Influence of iron based oxygen absorber in sachets of 500
cc obtained from Mitsubishi Gas Chemical Europe Ageless® on the
marmalade candies’ quality was tested during shelf life. Samples of
80±5 g were packaged in polymer pouches (110 mm x 110 mm),
hermetically sealed by MULTIVAC C300 vacuum chamber machine,
and stored in a room temperature +21±0.5 °C. The physiochemical
properties –moisture content, hardness, aw, pH, changes of
atmosphere content (CO2 and O2), ascorbic acid, total carotenoids,
total phenols in headspace of packs, and microbial conditions were
analysed before packaging and in the 1st, 3rd , 5th, 8th, 11th and 15th
weeks of storage.
Abstract: The research object was apple-black currant
marmalade candies. Experiments were carried out at the Faculty of
Food Technology of the Latvia University of Agriculture. An active
packaging in combination with modified atmosphere (MAP, CO2
100%) was examined and compared with traditional packaging in air
ambiance. Polymer Multibarrier 60 and paper bags were used.
Influence of iron based oxygen absorber in sachets of 500 cc
obtained from Mitsubishi Gas Chemical Europe Ageless® was tested
on the quality during the shelf of marmalade. Samples of 80±5 g
were packaged in polymer pouches (110 mm x 110 mm),
hermetically sealed by MULTIVAC C300 vacuum chamber machine,
and stored in room temperature +20.0±1.0 °C. The physiochemical
properties – weight losses, moisture content, hardness, aw, pH, colour,
changes of atmosphere content (CO2 and O2) in headspace of packs,
and microbial conditions were analysed before packaging and in the
1st, 3rd , 5th, 8th, 11th and 15th weeks of storage.
Abstract: Perishable goods constitute a large portion of retailer inventory and lose value with time due to deterioration and/or obsolescence. Retailers dealing with such goods required considering the factors of short shelf life and the dependency of sales on inventory displayed in determining optimal procurement policy. Many retailers follow the practice of using two bins - primary bin sales fresh items at a list price and secondary bin sales unsold items at a discount price transferred from primary bin on attaining certain age. In this paper, mathematical models are developed for primary bin and for secondary bin that maximizes profit with decision variables of order quantities, optimal review period and optimal selling price at secondary bin. The demand rates in two bins are assumed to be deterministic and dependent on displayed inventory level, price and age but independent of each other. The validity of the model is shown by solving an example and the sensitivity analysis of the model is also reported.