Storage stability of coconut milk powder

Spray-dried coconut milk powder prepared with additions of skim milk and dextrin was stored in packages for 6 months at room temperature (30°C and 80% RH). The packaging materials used were aluminum laminate (vacuum and air packed) and polypropylene. The sorption isotherm of the powder showed that the monolayer of water molecules was complete when the relative humidity was 27% which corresponded to a moisture content of 5%. Measurements of water activity, moisture content, peroxide value and solubility index indicated that lipid oxidation is the limiting factor in the stability of the powder. Its maximum shelf-life was 4 months when air or vacuum packaged in aluminum laminates and 1 1/2 months in polypropylene.     

Effect of oxygen absorber, nitrogen flushing, packaging material oxygen transmission rate and storage conditions on quality retention of raw whole unpeeled almond kernels (Prunus dulcis)

The present study investigated the effect of active packaging, nitrogen flushing, container oxygen barrier and storage conditions on quality retention of raw whole unpeeled almonds. Almond kernels were packaged in: a) polyethylene terephthalate//low-density polyethylene (PET//LDPE), and b) low-density polyethylene/ethylene vinyl alcohol/low-density polyethylene (LDPE/EVOH/LDPE) pouches under N_2, with or without an oxygen absorber, heat-sealed and stored for a period of 12 months. Quality parameters monitored were: peroxide value (PV), hexanal content, color, fatty acid composition and volatile compounds. PV ranged between 0.17 for fresh almonds and 9.22 meq O₂/kg oil for almonds packaged in PET//LDPE pouches under N₂ exposed to light at 20 °C after 12 months of storage. Respective values for hexanal were <28.5 μg/kg and 4.88 mg/kg. Polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFA) increased with a parallel decrease of monounsaturated fatty acids (MFA) after 12 months of storage in all treatments. Likewise, volatile compounds such as aldehydes, ketones, alcohols, alkanes and aromatic hydrocarbons increased indicating enhanced lipid oxidation. Color was the parameter least affected. Use of the oxygen absorber provided a shelf life of at least 12 months for all samples irrespective of container oxygen barrier, lighting conditions and storage temperature.     

Antioxidative effect of added dried Holy basil and its ethanolic extracts on susceptibility of cooked ground pork to lipid oxidation

Efficacy of varying concentrations of dried Holy basil powder and its ethanolic extracts in retarding oxidative rancidity was tested with cooked ground pork. The development of lipid oxidation products during 14 days refrigerated storage (5 °C) was evaluated by means of thiobarbituric acid-reactive substances (TBARS) value, peroxide value (POV), conjugated diene and hexanal content. In the amounts studied, dried Holy basil powder and its ethanolic extract significantly (P < 0.05) inhibited the formation of TBARS, peroxide, conjugated dienes and hexanal in a dose-dependent manner. The oxidation process was significantly (P < 0.05) influenced by the type of antioxidant and its concentration. Addition of dried Holy basil powder to cooked ground pork was more effective in inhibiting lipid oxidation than its ethanolic extracts. Additionally, TBARS values and hexanal contents in cooked ground pork were highly correlated (r² = 0.95; P < 0.05) with each other.     

Oxidation of linoleic acid as a marker for shelf life of corn flour

The objective of this study was to measure the oxidation of linoleic acid of nixtamalised corn masa (NCM) during an accelerated shelf life study at high temperature (45–85 °C), and 0.45 a_w for 180 days. Linoleic acid (LA) was present at 55.1%, followed by oleic acid (26.9%), as measured by gas chromatography. The propagation of lipid oxidation, measured by anisidine value, reached its peak 2–5 days after the peroxide value had passed over its maximum value. At this time, flour showed at least a 10% reduction of LA; but, at the end of storage only 10% of LA remained. The autocatalytic oxidation of linoleic acid in NCM was temperature-dependent, with Q₁₀ = 1.4. The index of quality loss for corn flour stored at 55 °C was 0.48% per day; under these conditions 50% of its quality decreased in only 104 days. Mathematical modelling estimates a shelf life of 84 days for corn masa (<6 meq/kg peroxide) stored at 25 °C.     

Effects of tea polyphenol coating combined with ozone water washing on the storage quality of black sea bream (Sparus macrocephalus)

The present research evaluated the effects of tea polyphenol (TP) combined with ozone water (O₃) on the quality of black sea bream (Sparus macrocephalus) over a period of 15 days storage at 4 °C. A solution of TP (0.2%, w/v) was used to coat the fish after washing with ozone water (1 mg/L). Fish physicochemical (pH, K value, peroxide value, thiobarbituric acid, total volatile basic nitrogen, trimethylamine, texture, and colour), sensory, and bacteriological characteristics were all analysed. TP + O₃ treatment effectively reduced nucleotide breakdown, lipid oxidation, protein decomposition, and microbial growth, and maintained better characteristics of texture, colour, and sensory compared with the control. The efficiency of TP + O₃ treatment was also better than that of TP treatment or O₃ treatment alone. Therefore, tea polyphenol coating combined with ozone water prewashing may be a promising method of maintaining the storage quality of black sea bream and of extending fish post-mortem shelf-life during 4 °C storage.     

Novel interactions of caffeic acid with different hemoglobins: Effects on discoloration and lipid oxidation in different washed muscles

Caffeic acid (CA) accelerated methemoglobin (Hb) formation at pH 5.8 and 25 °C. This was attributed to electron donation from CA to liganded O₂ in Hb. CA inhibited hemin dissociation from metHb. Pig Hb remained mostly as oxyHb and did not promote lipid oxidation in washed cod muscle (WCM) nor washed turkey muscle (WTM) during iced storage at pH 5.8. Conversely, perch Hb rapidly was converted to metHb and readily promoted lipid oxidation based on lipid peroxide and hexanal formation. CA strongly inhibited perch Hb-mediated lipid oxidation during storage. Once metHb formation occurred in WCM, CA appeared to maintain the heme protein as metHb during the remainder of iced storage. CA may have become bound to perch Hb based on filtration analysis. CA facilitated the transfer of perch Hb (but not pig Hb) from the aqueous phase to the insoluble components of WCM. Collectively, these results suggest that CA inhibited Hb-mediated lipid oxidation by various mechanisms not related to inhibition of metHb formation.     

The use of peroxide value as a measure of quality for walnut flour stored at five different temperatures using three different types of packaging

Walnut flour, a by-product from the production of cold-pressed walnut oil, can contain up to 20% oil, which contains high levels of polyunsaturated fatty acids and is, therefore, potentially unstable. In this experiment, ground walnut flour was stored in three types of container, polypropylene plastic containers, multi-walled plastic-lined paper bags and manila (brown) paper bags. These containers were stored at mean temperatures of −24.6, 3.3, 10.4, 14.3 and 23.0 °C for 26 weeks. The moisture content and the peroxide value of the oil extracted from the flour were determined every four weeks for 26 weeks. The initial peroxide value of the freshly ground flour was 0.01 ± 0.008 meq O₂/kg oil.     

ACCELERATED STORAGE, SHELF LIFE AND COLOR OF MANGO POWDER

Vacuum‐dried mango powder was produced from mango pulp through the addition of glycerol monostearate and tricalcium phosphate at 0.015 kg each per kg mango solids and maltodextrin at 0.62 kg per kg dry mango solids. The mango powder was packed in aluminum foil‐laminated pouches and stored in an accelerated storage environment maintained at 90% relative humidity (RH) and 38 ± 2C. The sticky‐point moisture content at 38 ± 2C was considered as the maximum moisture content to which the mango powder would remain stable. The shelf life of the powder predicted from this consideration and the Guggenheim‐Anderson‐de Boer (GAB) model for the water activity moisture content relationship was 114.68 days, whereas the actual shelf life was 105 days. The color change of the powder during storage followed first‐order reaction kinetics with a rate constant of 0.038 per day.     

Antioxidant and antimicrobial effects of garlic in chicken sausage

The antioxidant and antimicrobial effects of equivalent concentrations of fresh garlic (FG), garlic powder (GP) and garlic oil (GO) were investigated against lipid oxidation and microbial growth in raw chicken sausage during storage at 3°C. The antioxidant activities were compared to that of a standard synthetic antioxidant; butylated hydroxyanisole (BHA). The initial mean levels of thiobarbituric acid (TBA) value and peroxide value (POV) were 0.140 and 6.32, respectively. However after 21 days of storage, TBA and POV ranged from 0.151 to 4.92, respectively, in FG (50 g/kg) formulated samples to 0.214 and 8.64, respectively, in GO (0.06 g/kg) formulation. Addition of either garlic or BHA (0.1 g/kg) significantly delayed lipid oxidation when compared with control. The antioxidant activities of the various materials added followed the order FG>GP>BHA>GO. On the other hand, the initial aerobic plate count (APC) in the samples was 4.41 log₁₀ CFU/g. Addition of FG (30 g/kg) or GP (9 g/kg) significantly reduced the APC and, subsequently, the shelf-life of the product was extended to 21 days. However, addition of GO or BHA resulted in no significant difference in APC when compared with control. Sensory analysis indicated that FG had a significant stronger flavor than the other sausage formulations. The results suggest that fresh garlic and garlic powder, through their combined antioxidant and antimicrobial effects, are potentially useful in preserving meat products.     

Synergistic effect of tannic acid and modified atmospheric packaging on the prevention of lipid oxidation and quality losses of refrigerated striped catfish slices

Chemical, microbiological and sensorial changes of striped catfish (Pangasius hypophthalmus) slices treated without and with tannic acid (100 and 200 mg/kg) were determined during 15 days of storage at 4 °C in air and under modified atmospheric packaging (MAP, 60% N₂/35% CO₂/5% O₂). The slices consisted of 9.2 g lipid/100 g and the lipid contained 64.55% unsaturated fatty acids and 33.87% saturated fatty acids. During the storage, the sample treated with 200 mg/kg tannic acid and stored under MAP (M₂) had the lowest peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) with the coincidental lowest non-haem iron content, indicating the retarded lipid oxidation. Fourier transform infrared (FTIR) spectra indicated the formation of primary oxidation products and free fatty acids in M₂ sample after 15 days. Conversely, these compounds were found at lower contents in the control samples kept in air without tannic acid treatment (A₀), suggesting that the deterioration was more advanced. Myosin heavy chain of A₀ was degraded by 17.85% after 15 days of storage, whereas no change was noticeable in M_2, compared with the fresh sample (F). Based on microbiological acceptability limit (10⁷ cfu/g), the shelf-life of A₀ and M₂ was estimated to be 3 and 15 days, respectively. M₂ had the acceptable scores for all sensory attributes up to 15 days, while A₀ was acceptable when stored for 9 days. Therefore, tannic acid exhibited a synergistic effect with MAP on retarding lipid oxidation and microbial growth, thereby increasing the shelf-life of striped catfish slices during refrigerated storage.     

Evaluation of lipid oxidation in spaghetti pasta enriched with long chain n−3 polyunsaturated fatty acids under different storage conditions

This study investigated lipid oxidation in spaghetti enriched in long chain n−3 polyunsaturated fatty acids (LC n−3 PUFA) by the addition to semolina of an integrator containing eicosapentaenoic acid and docosahexaenoic acid. Two oxidative parameters were evaluated: peroxide value (PV), to assess primary oxidation and oxidised fatty acids to quantify secondary oxidation products. Functional spaghetti had a shelf life comparable to control pasta. LC n−3 PUFA were not significantly implicated in the onset of oxidation in spaghetti stored under daylight and accelerated oxidation in a laboratory heater. Storage decidedly affected shelf life: PV in functional spaghetti increased from 7.1 to 43.4 meq O₂/kg of fat under light exposure over 12 months, and from 7.1 to 16.2 meq O₂/kg under accelerated ageing at 55 °C for 27 days, reproducing about 18 months at room temperature. Oxidised fatty acids increased in fortified spaghetti from 4.8 to 13.8 g/100 g of fat under light exposure over 12 months and from 4.8 to 7.8 g/100 g of fat at 55 °C in 27 days. The high sensitivity of spectrophotometric and chromatographic analytical methods permitted the evaluation of primary and secondary oxidative derivatives in small amounts of fat.     

Effects of type of packaging material on physicochemical and sensory characteristics of deep‐fat‐fried banana chips

A storage study of deep‐fat‐fried banana chips was carried out for 8 weeks at ambient temperature (27 °C), using four types of packaging material: laminated aluminium foil (LAF), oriented polypropylene (OPP), polypropylene (PP) and low‐density polyethylene (LDPE). The physicochemical and sensory characteristics of the stored banana chips were analysed at weeks 0, 2, 4, 6 and 8. The quality parameters determined were moisture content, water activity (a_w), thiobarbituric acid‐reactive substances (TBARS), texture (breaking force), colour and sensory attributes. The moisture content, a_w, TBARS and breaking force values of all samples increased during storage. The colour also changed during storage, showing higher L and lower a and b values. Samples packed in LAF had the lowest moisture content, a_w, TBARS and breaking force values. The most notable sensory change that occurred during storage was a decrease in crispness. Samples packed in LAF had higher scores than the other three samples, whilst LDPE gave the lowest scores for crispness as well as product colour. There were no significant differences (P > 0.05) in rancid odour among samples packed in OPP, PP and LDPE. However, there were significant differences (P < 0.05) between samples packed in LAF and the other three samples, with LAF giving the lowest rancid odour. © 2002 Society of Chemical Industry     

Effect of processing and storage of Jameed on conjugated linoleic acid content and fat and cholesterol oxidation

The influence of Jameed processing and storage on fat and cholesterol oxidation, hydrolytic rancidity, and conjugated linoleic acid (CLA) was evaluated by determining peroxide value (PV), 7-ketocholesterol, free fatty acids content (FFAs) and total CLA. Three different sizes of Jameed pieces (ca. 50, 200 and 400 g balls) were used to investigate the influence of storage for 0, 1, 3, 5 and 7 months on the above lipid oxidation parameters. No significant (P>0.05) effect of the Jameed processing steps on lipid changes was found with the exception of the sun drying steps, that caused an increase of PV, 7-ketocholesterol and FFA contents and a decrease in CLA content. This trend was also observed during storage of Jameed at room temperature and kept exposed to light and atmospheric air. The PV values of the 50, 200 and 400 g balls after 7 months of storage were 35.3, 19.4 and 20.4 meq O₂ kg⁻¹ of fat, that were 17, 11 and 12 times higher compared with the corresponding values of the fresh samples (1.9 meq O₂ kg⁻¹ of fat ). The 7-ketocholesterol of the tested samples increased from about 5.7 μg g⁻¹ to 210, 120 and 125 μg g⁻¹ for the 50, 200 and 400 g balls, respectively. FFA content increased remarkably during storage, from about 1.3 g kg⁻¹ at the beginning of storage to 8.6 g kg⁻¹ of fat after 7 months with no significant (P>0.05) effect for the size of Jameed pieces on FFAs content. On the contrary, a decrease of about 43%, 26% and 26% of the original value (5.7 mg kg⁻¹ of fat) in CLA content was found for the stored Jameed pieces of 50, 200 and 400 g, respectively.     

Anti-oxidant effect of extracts of kinnow rind,pomegranate rind and seed powders in cooked goat meat patties

To overcome the disadvantages of using synthetic anti-oxidants in meat products, an investigation was carried out to evaluate the anti-oxidant effect of extracts of fruit by-products viz., kinnow rind powder (KRP), pomegranate rind powder (PRP) and pomegranate seed powder (PSP) in goat meat patties. Total phenolics content, DPPH radical scavenging activity and effect of these extracts on instrumental color, sensory attributes and TBARS values during storage (4 ± 1 °C) of goat meat patties were evaluated. Results showed that these extracts are rich sources of phenolic compounds having free radical scavenging activity. Hunter Lab L value significantly (P < 0.05) lowered in PRP followed by PSP and KRP patties. Sensory evaluation indicated no significant differences among patties. Further, a significant (P < 0.5) reduction in TBARS values (lipid oxidation) during storage of goat meat patties was observed in PRP, PSP and KRP as compared to control patties. Average TBARS values (mg/kg meat) during refrigerated storage (4 ± 1 °C) were significantly lower in PRP, followed by PSP and KRP as compared to control. The overall anti-oxidant effect was in the order of PRP > PSP > KRP. It was concluded that extracts of above fruits by-product powders have potential to be used as natural anti-oxidants in meat products.     

Microencapsulation of Lactobacillus acidophilus La-5 by spray-drying using sweet whey and skim milk as encapsulating materials

The aim of this study was to evaluate the effect of encapsulating material on encapsulation yield, resistance to passage through simulated gastrointestinal conditions, and viability of Lactobacillus acidophilus La-5 during storage. Microparticles were produced from reconstituted sweet whey or skim milk (30% total solids) inoculated with a suspension of L. acidophilus La-5 (1% vol/vol) and subjected to spray-drying at inlet and outlet temperatures of 180°C and 85 to 95°C, respectively. The samples were packed, vacuum-sealed, and stored at 4°C and 25°C. Encapsulation yield, moisture content, and resistance of microencapsulated L. acidophilus La-5 compared with free cells (control) during exposure to in vitro gastrointestinal conditions (pH 2.0 and 7.0) were evaluated. Viability was assessed after 0, 7, 15, 30, 45, 60, and 90 d of storage. The experiments were repeated 3 times and data were analyzed by ANOVA and Tukey test for the comparison between means. The encapsulating material did not significantly affect encapsulation yield, average diameter, or moisture of the particles, which averaged 76.58 ± 4.72%, 12.94 ± 0.78 μm, and 4.53 ± 0.32%, respectively. Both microparticle types were effective in protecting the probiotic during gastrointestinal simulation, and the skim milk microparticles favored an increase in viability of L. acidophilus La-5. Regardless of the encapsulating material and temperature of storage, viability of the microencapsulated L. acidophilus La-5 decreased on average 0.43 log cfu/g at the end of 90 d of storage, remaining higher than 10⁶ cfu/g.     

Effect of packaging under vacuum or under nitrogen on the keeping quality of Danedar khoa

A khoa variety popularly known as Danedar khoa, which has a very short life under ambient conditions, was studied for its shelf life at room and refrigerated temperatures under controlled conditions after packaging in a flexible material (poster paper/aluminium foil/low-density polyethylene [LDPE]). The samples were observed periodically for characteristics such as moisture content, peroxide value, titratable acidity and overall acceptability. Samples packed under nitrogen and stored under refrigeration were found to be distinctly superior in all respects.     

Modified atmosphere packaging and vacuum packaging for long period chilled storage of dry-cured Iberian ham

Dry-cured Iberian ham slices were stored under vacuum and under four different modified atmospheres (60/40 = 60%N₂ + 40%CO₂; 70/30 = 70%N₂ + 30%CO₂; 80/20 = 80%N₂ + 20%CO₂; argon = 70%argon + 30%CO₂) at 4 ± 1 °C during 120 days. Gas composition, moisture content, pH, colour, pigment content, and lipid stability were measured, as well as sensory and microbial analysis were carried out throughout storage. A loss of intensity of red colour (a^*-values) was observed during storage in ham slices (P < 0.05). Consistently, MbFe(II)NO content also decreased throughout storage (P > 0.05). Slices of ham packed in 40%CO₂ (60/40) and 30%CO₂ (70/30) showed lower a^*-values than the rest of the batches after 60 days (P < 0.05), though differences were not evident after 120 days (P > 0.05). TBARs values showed an upward trend during the storage of packaged slices (P < 0.05). Vacuum-packed slices showed the lowest TBARs values and those packed with 40%CO_2, the highest. Sensory attributes did not vary significantly (P > 0.05) throughout storage under refrigeration and packed either in vacuum or in modified atmospheres. No safety problems were detected in relation to the microbial quality in any case.     

Headspace volatile composition and oxidative storage stability of pressed marama bean (Tylosema esculentum) oil

Marama bean (Tylosema esculentum) is an underutilised legume indigenous to the Kalahari Desert region of southern Africa. The bean has high lipid content and hence is a potential source for production of edible oil. The headspace volatile composition of freshly pressed marama bean oil was explored and the oil was further studied during 7 months of storage under different light and temperature conditions. The oxidative stability of the oil was examined by measuring peroxide value, vitamin E content and FT-IR spectra. Additionally, the headspace volatile composition of the oil was investigated during storage by use of dynamic headspace GC–MS. The results showed that marama oil is highly stable and has good natural antioxidant properties; enzymatic lipid oxidation does not take place in marama oil. Light has a greater effect on the lipid oxidation than has temperature, and hence marama oil should preferably be stored in darkness and rather at 25 °C than 35 °C. Under these conditions, the marama oil has a shelf life of at least 7 months.     

Shelf life prediction of packaged cassava-flour-based baked product by using empirical models and activation energy for water vapor permeability of polyolefin films

Moisture sorption kinetics and isotherms of cassava-flour-based baked product were investigated. Empirical models were tested to fit the experimental data. Textural changes of the product were investigated. In addition, activation energies (E_p) for water vapor permeability (WVP) of polyolefin films were determined. Finally, the product was packaged in low-density polyethylene (LDPE) or oriented polypropylene (OPP) pouches, and stored at 30 ± 1 °C and 50 ± 2% RH to simulate actual storage conditions and to determine shelf life. This actual shelf life was compared to the predicted shelf life by using empirical models and E_p for WVP. Moisture sorption kinetics was more rapid during the initial stage, while a lesser amount of moisture was adsorbed as adsorption time increased. The higher the relative humidity used, the more pronounced the effect. The sigmoidal moisture sorption isotherms of this product can be classified as type II. The GAB model was found to be the best-fit model for this product. Once the product hardness or work reached the maximum and began to reduce at moisture content (MC) ≈6%, the product texture began to be detected as becoming slightly soft. This implies that hardness and work at the maximum level could be used to identify the critical MC which causes a loss of crispness to an unacceptable degree. The predicted shelf lives – estimated by employing E_p for WVP of LDPE and OPP, and the GAB model – were close to the actual shelf lives. Therefore, the estimation by empirical models and activation energy was found to be applicable for rapid and accurate shelf life prediction.