A new,simple method for the production of meat-curing pigment under optimised conditions using response surface methodology

The production of cured meat pigment using nitrite and ascorbate in acidic conditions was evaluated. HCl, ascorbate and nitrite concentrations were optimised at three levels using the response surface method (RSM). The effects of process variables on the nitrosoheme yield, the wavelength of maximum absorbance (λ_max), and L*, a* and b* values were evaluated. The response surface equations indicate that variables exerted a significant effect on all dependent factors. The optimum combinations for the reaction were HCl = − 0.8, ascorbate = 0.46 and nitrite = 1.00 as coded values for conversion of 1 mM hemin to nitrosoheme, by which a pigment yield of 100%, which was similar to the predicted value of 99.5%, was obtained. Likewise, the other parameters were not significantly different from predicted values as the λ_max, L*, a* and b* values were 558 nm, 47.03, 45.17 and 17.20, respectively. The structure of the pigment was identified using FTIR and ESI/MS.     

Impact of cryoconcentration on casein micelle size distribution,micelles inter-distance,and flow behavior of skim milk during refrigerated storage

Cryoconcentration combined with a cascade effect was used to concentrate skim milk up to 25.12% total dry matter. Size, shape, and inter-micellar distance of casein micelles were characterized by ZetasizerNano-ZS, transmission electron microscopy, and ImageJ analyses. Flow properties of the cryoconcentrated skim milk were evaluated during 5 weeks of storage under refrigerated condition at 4 °C. Milk color was also evaluated according to the L*, a*, and b* system. The cryoconcentrated skim milk obtained after three cryoconcentration cycles was characterized by a monomodal distribution of its micelles with a tendency to smaller casein micelles. Approximately 60% of the total micellar volume was occupied by the casein micelles with a size of 100–200 nm, less than 18% of the volume with a size of 50–100 nm and only less than 1% was occupied by micelles with a size > 350 nm. This result shows that cryoconcentration changed the distribution of the mean size of the casein micelles to smaller units. No significant difference was observed on the inter-micellar distance. Cryoconcentration significantly improved the color of skim milk by increasing the L* value up to 67 which was similar to that of whole milk. Transition from a Newtonian to a non-Newtonian behavior was observed from the fourth week storage with a slight increase of casein micelle size.Industrial relevanceA concentration procedure of skim milk based on a complete block cryoconcentration technique was proposed. Application of this sub-zero technology permitted the concentration of skim milk total dry matter up to 25%. The casein micelle size was positively affected by moving the major part of the micelles toward the smaller size, whereas the inter-micellar distance was not affected. This new knowledge can be exploited in milk-based products to enhance the product stability. The cryoconcentrated skim milk color was positively affected since its L* value, which represents the milk whiteness, was significantly improved. The flow behavior of the cryoconcentrated milk was of Newtonian type up to 4 weeks of storage at 4 °C. The generated knowledge in this study can be easily used by the milk processing industry in order to make stable milk product with high dry matter content without adding milk powder, which negatively affects the product sensory properties (floury consistency).     

Effect of active and modified atmosphere packaging on quality retention of dark chocolate with hazelnuts

The present study investigated the effect of active and modified packaging as well as packaging material oxygen permeability on quality retention of dark chocolate with hazelnuts. Dark chocolate was packaged in: a) polyethylene terephthalate//low density polyethylene (PET//LDPE), and b) polyethylene terephthalate coated with SiOx//low density polyethylene (PET-SiOx//LDPE). Samples were packaged either under, vacuum or N₂ or with an oxygen absorber and stored in the dark at 20 °C for a period of 12 months. “Commercial” control samples for comparison purposes consisted of chocolate packaged in aluminum foil in air while “model” control samples used for sensory evaluation consisted of chocolate packaged in glass jars and stored at ? 18 °C. Quality parameters monitored were: peroxide value, hexanal content, color, fatty acid composition and volatile compounds. Of the sensory attributes color, texture, odor and taste were evaluated. PV ranged between 0.80 for fresh dark chocolate with hazelnuts and 6.51 meq O₂/kg chocolate fat for commercially packaged samples after 12 months of storage. Respective values for hexanal were 0.53 and 7.56 mg/kg. % Saturated fatty acids (SFA) increased with a parallel decrease in monounsaturated fatty acids (MFA) and polyunsaturated fatty acids (PUFA) after 12 months of storage mainly in least protected samples (commercial package). Likewise, after 12 months of storage an increase in concentration of aldehydes, ketones, alcohols and alkanes (p < 0.05) with a parallel decrease in pyrazines where observed especially in case of least protected products after 6 and 12 months of storage. In general after 12 months of storage chocolate showed whitening of the surface resulting to an increase in L* and a* values (p < 0.05) and a decrease in b* value. Dark chocolate with hazelnuts retained acceptable quality for ca. 8 months in commercial packages. For samples packaged in PET//LDPE irrespective of storage atmosphere the shelf life was 8 to 9 months and for samples packaged in PET-SiOx//LDPE irrespective of storage atmosphere the shelf life was 11 months. Finally for samples packaged with an oxygen absorber irrespective of packaging material the shelf life was at least 12 months.Industrial relevanceChocolate packaged with an oxygen absorber in a barrier packaging material will maintain its aroma, taste and nutritional quality substantially longer than other packaging methods.     

Influence of reuterin-producing Lactobacillus reuteri coupled with glycerol on biochemical,physical and sensory properties of semi-hard ewe milk cheese

The biochemical, physical and sensory characteristics of ewe milk cheeses made with reuterin-producing Lactobacillus reuteri and glycerol (substrate for reuterin production) were assessed. Cheese made with lactococci starter (CTRL), cheese made with starter and L. reuteri (SLR), and cheese made with starter, L. reuteri and 30 mM glycerol (SLR-G) were manufactured. L. reuteri reached counts above 7 log cfu/g on day 1. Lactococci survival was enhanced in SLR cheese without affecting cheese pH, dry matter, proteolysis, concentration of most free amino acids (FAA), textural and most color parameters, or sensory characteristics. In situ production of reuterin by L. reuteri was only detected in SLR-G cheese, decreasing LAB counts although acidification remained unaffected. SLR-G cheese showed higher values of cell free aminopeptidase activity, overall proteolysis and FAA, particularly glutamic acid, than CTRL and SLR cheeses. The addition of L. reuteri-glycerol resulted in lower hardness and elasticity values in SLR-G cheese and influenced its L*, a* and b* color parameters. However, these changes, which were detected by instrumental analysis, did not affect the sensory scores for texture and color quality of SLR-G cheese, and it received the highest scores for taste quality. Our results suggest that L. reuteri-glycerol may provide a suitable system to release the antimicrobial reuterin in cheese without affecting negatively its sensory characteristics.     

Effect of carbon monoxide in modified atmosphere packaging,storage time and endpoint cooking temperature on the internal color of enhanced pork

The objective of this research was to evaluate the effects of gas atmosphere, refrigerated storage time, and endpoint temperature on internal cooked color of injection-enhanced pork chops. Enhanced chops were packaged in 0.36% CO/20.34% CO₂ (CO-MAP), 80% O₂/20% CO₂ (HO-MAP), or PVC-overwrapped (PVC-OW; controls), stored at 4 °C for 0, 12, 19 or 26 days, displayed for 2 days then cooked to six endpoint temperatures (54, 60, 63, 71, 77, and 82 °C). L¹, a¹, and b¹ values, hue angle and chroma were determined on the internal cut surface of cooked chops. Chops packaged in CO-MAP had the highest a¹ values; a¹ value began increasing on day 14. The lowest hue angles occurred in chops cooked to lower endpoint temperatures. Chops in CO-MAP had lower hue angles and higher chroma than those in HO-MAP and PVC-OW. Above 71 °C, hue angle and chroma increased. Overall, CO-MAP packaged chops stored for longer time periods then cooked to lower endpoint temperatures appeared reddest. HO-MAP packaged chops were less red, did not change over time, and appeared more well done at lower endpoint temperatures than those in other gas atmospheres. CO-MAP packaged chops retained redness even after cooking at 82 °C.     

Effect of single-cycle and multiple-cycle high-pressure treatments on the colour and texture of chicken breast fillets

High-pressure processing, a useful tool to improve the microbiological quality and safety of foods, may also bring about changes in the colour and texture of foods, which might influence their acceptability by consumers. In the present work, the effect of single-cycle and multiple-cycle high-pressure treatments at 400 MPa on the colour and texture of chicken breast fillets was investigated. Colour parameters L*, a* and b* were significantly higher for all pressurized fillets than for the vacuum-packaged control fillets. When single-cycle treatments were applied, maximum values of texture parameters were generally found for fillets pressurized for 10 or 15 min, depending on whether Kramer or Warner-Bratzler cells were used, and decreased for fillets submitted to longer cycles. In the case of multiple-cycle treatments, texture parameters initially increased with the number of 1-min cycles, but fillets submitted to the most severe treatments showed lower values.Industrial relevanceThe objective of the present study was to evaluate the effect of single-cycle and multiple-cycle high-pressure processing at 400 MPa on the colour and texture of chicken breast fillets. Significant changes in colour occurred even for the shortest treatment applied, a 1-min cycle. Texture parameters increased with length of treatment, but beyond a certain severity of treatment these parameters declined. Acceptability by consumers, and marketing of high-pressure treated chicken breast fillets, might be negatively affected by changes in visual appearance.     

Comparison of Minolta colorimeter and machine vision system in measuring colour of irradiated Atlantic salmon

BACKGROUND: Minolta and machine vision are two different instrumental techniques used for measuring the colour of muscle food products. Between these two techniques, machine vision has many advantages, such as its ability to determine L*, a*, b* values for each pixel of a sample's image and to analyse the entire surface of a food regardless of surface uniformity and colour variation. The objective of this study was to measure the colour of irradiated Atlantic salmon fillets using a hand‐held Minolta colorimeter and a machine vision system and to compare their performance. RESULTS: The L*, a*, b* values of Atlantic salmon fillets subjected to different electron beam doses (0, 1, 1.5, 2 and 3 kGy) were measured using a Minolta CR‐200 Chroma Meter and a machine vision system. For both Minolta and machine vision the L* value increased and the a* and b* values decreased with increasing irradiation dose. However, the machine vision system showed significantly higher readings for L*, a*, b* values than the Minolta colorimeter. Because of this difference, colours that were actually measured by the two instruments were illustrated for visual comparison. Minolta readings resulted in a purplish colour based on average L*, a*, b* values, while machine vision readings resulted in an orange colour, which was expected for Atlantic salmon fillets. CONCLUSION: The Minolta colorimeter and the machine vision system were very close in reading the standard red plate with known L*, a*, b* values. Hence some caution is recommended in reporting colour values measured by Minolta, even when the ‘reference’ tiles are measured correctly. The reason for this discrepancy in colour readings for salmon is not known and needs further investigation. Copyright © 2009 Society of Chemical Industry     

High pressure treatments on the inactivation of Salmonella Enteritidis and the characteristics of beef carpaccio

The effect of high pressure (HP) on Salmonella enterica subsp. enterica serovar Enteritidis in beef carpaccio stored under temperature abuse conditions (8 °C) during 30 days was investigated. After treatment, reductions of S. Enteritidis were 3.68 and 5.94 log cfu/g in samples pressurized at 450 MPa for 5 and 10 min, respectively, whereas the pathogen was only detected after enrichment of samples treated at 450 MPa for 15 min. During storage, counts of S. Enteritidis decreased 0.26 log cfu/g in non-pressurized carpaccio, 1.33 log cfu/g in carpaccio treated at 450 MPa for 5 min and were only detected after enrichment in carpaccio pressurized at 450 MPa for 10 or 15 min. Color (L*, a* and b*) varied with pressurization and storage, with higher changes in carpaccio treated at longer pressurization times. Shear resistance was slightly lower in treated samples just after pressurization, but increased at the end of the storage period. Maximum force was less affected by treatment.     

Color,sensory and textural attributes of beef frankfurter,beef ham and meat-free sausage containing tomato pomace

The present investigation focuses on the textural properties, sensory attributes and color changes of beef frankfurter, beef ham and meat-free sausage produced by different levels of bleached tomato pomace. The texture and color profile were performed using an instrumental texture analyzer and colorimeter. The findings indicated that tomato pomace-added sausages had higher water holding capacity (WHC) compared to that of commercial samples. The frankfurters containing 5 and 7% (w/w) tomato pomace had the highest redness (a*), chroma (C*) and color differences (ΔE) values, while the meat-free sausages containing 7% (w/w) tomato pomace had significant (p < 0.05) values for lightness (L*) and yellowness (b*). Furthermore, there were no significant (p > 0.05) color differences between beef ham samples (with and without tomato pomace). A significant progression in the textural hardness and chewiness of systems containing tomato pomace was observed as well as higher sensory scores by panelists. According to sensorial evaluations, bleached tomato pomace improved the consumer acceptability and preference.     

Reuterin,lactoperoxidase, lactoferrin and high hydrostatic pressure treatments on the characteristics of cooked ham

The effect of reuterin, lactoperoxidase system (LPS) and lactoferrin (LF) combined with high hydrostatic pressure (HHP) on the characteristics of sliced cooked ham during 35 days at 4 and 10 °C were investigated. Reuterin and LPS inhibited the growth of total microorganisms during 35 days at 4 and 10 °C, whereas a regrowth at 10 °C was observed when HHP was applied. Combined treatments kept total viable counts below 1.5 log cfu/g after 35 days at 10 °C. Regarding the effect of treatments on colour of cooked ham, LPS alone or in combination with HHP slightly affected L*, a* and b* values, but these changes tended to attenuate during storage. Likely, slight differences were registered in shear strength values among control and treated cooked ham. The accumulation of volatile compounds was reduced in cooked ham treated with LPS and LF in combination with HHP, even under abuse temperature conditions (10 °C).Industrial relevanceLPS applied in combination with HHP was the most effective treatment at reducing the growth of total microorganisms in refrigerated cooked ham with minor changes in its characteristics. The antimicrobial activity of such combined treatment against food-borne pathogens, which has also been reported in RTE foods, points to its usefulness to assure a safe product of sensory characteristics similar to those of untreated cooked ham.     

High pressure effect on the color of minced cured restructured ham at different levels of drying, pH, and NaCl

Color changes of minced cured restructured ham was studied considering the effects of high pressure (HP) treatment (600 MPa, 13 °C, 5 min), raw meat pH₂₄ (low, normal, high), salt content (15, 30 g/kg), and drying (20%, 50% weight loss). Raw hams were selected based on pH₂₄ in Semimembranosus, mixed with additives, frozen, sliced, and dried using the Quick-Dry-Slice® process. Meat color (CIE 1976 L*a*b*) and reflectance spectra were measured before and after HP treatment. HP significantly increased L*, decreased a*, and decreased b* for restructured ham dried to 20% weight loss, regardless of salt content and pH₂₄. L* and a* were best preserved in high pH/high salt restructured ham. HP had no effect on the color of restructured ham dried to 50% weight loss. HP had no effect on the shape of reflectance curves, indicating that the pigment responsible for minced cured restructured ham color did not change due to HP.     

Exit of seed weevil and its parasitoid changed testa color but not phenolic and tannin contents in faba beans

Seeds of eight faba bean accessions, grown under field conditions, were subjected to L*a*b* (L*, lightness; a* redness; b* blueness) scale examination and phenolic and tannin determination after classification as intacts, bruchid- and parasitoid-damaged. Accessions differed in testa color and phenolic and tannin contents. L* and b* were negatively correlated with phenolics and tannins while a* was positively correlated with phenolics. Bruchid- and parasitoid-damaged seeds had increased a* indicating a shift of testa color tο red but phenolics and tannins did not differ between seed classes. Thus, testa discoloration in insect-damaged seeds was not the result of oxidation of phenolics but possibly due to Maillard reaction indicating accelerating aging of seeds.     

KINETIC MODELINGS OF BROCCOLI COLOR CHANGES DURING CHILLED STORAGE

This work studied the kinetic models of broccoli color changes during storage. The Commission Internationale d'Eclairage ([CIE] International Commission on Illumination)‐L*a*b* color system parameters a*, b*, H°, total color difference (TCD), chlorophyll content and yellowness degree were used to determine the color changes under the storage conditions at 0, 5 and 10C. The broccoli ball was packed with high‐density polyethylene film. The experimental results showed that the package greatly promoted the activation energy of b* value in broccoli while delaying the respiration peak. The nonlinear regression analysis showed that the rate constants of color parameters b* and TCD were following a first‐order Arrhenius‐type reaction depending on temperature, and the polynomial model was suitable for the changes of a* and H° value. The observed results demonstrated that the variation of color parameters was in accordance with chlorophyll content and yellowness degree in stored broccoli, suggesting the possibility of a computer‐vision system application on the color grading of broccoli.     

Freshness assessment of gilthead sea bream (Sparus aurata) by machine vision based on gill and eye color changes

The fish freshness was evaluated using machine vision technique through color changes of eyes and gills of farmed and wild gilthead sea bream (Sparus aurata), being employed lightness (L^*), redness (a^*), yellowness (b^*), chroma (c^*), and total color difference (ΔE) parameters during fish ice storage. A digital color imaging system, calibrated to provide accurate CIELAB color measurements, was employed to record the visual characteristics of eyes and gills. The region of interest was automatically selected using a computer program developed in MATLAB software. L^*, b^*, and ΔE of eyes increased with storage time, while c^* decreased. The a^* parameter of fish eyes did not show clear a trend with storage time. The L^*, b^*, and ΔE of fish gills increased with storage time, but a^* and c^* decreased. Regression analysis and artificial neural networks approaches were used to correlate the eyes and gills color parameters with the time of storage and a strong correlation was found between color parameters and storage day. Gills color changes were more precise than those found for eyes in order to evaluate the fish freshness. However, the gills cover should be removed for taking the images and thus, the method is destructive and time-consuming. Therefore, the color parameters of fish eyes can be used as a green, low cost and easy method for fast and on-line assessing of fish freshness in food industry.     

Aging of red wines made from hybrid grape cv. BRS Violeta: Effects of accelerated aging conditions on phenolic composition,color and antioxidant activity

Aging is an enological technique usually employed with Vitis vinifera wines for improving and stabilizing wine sensory attributes like red wine color. However, red wines made from non-vinifera grape cultivars are considered not suitable for classic wine aging because they are prone to color loss during processing and storage, mainly due to the major occurrence of non-acylated anthocyanidin 3,5-diglucosides. The recently developed hybrid grape cv. BRS Violeta gives rise to deep red-purplish colored wines characterized by an important contribution of p-coumaroylated anthocyanidin 3,5-diglucosides. In this work, Violeta red wines were subjected to control (storage at 15 °C) and accelerated (storage at 25, 35 and 50 °C) aging for 120 days. Total phenolic content was only significantly decreased by 23% in accelerated aged wines at 50 °C, whereas antioxidant capacity was mainly reduced in the first 20 days of aging (around 35% for all the wines, except for 45% for wine aged at 50 °C) and then remained almost stable. In contrast, total anthocyanin content decreased following expected first-order kinetics and the variation of rate constants with regard to temperature fitted well with an Arrhenius-type equation. The calculated activation energy for disappearance of anthocyanins (47 kJ/mol) was close to the lower limit of the range of values reported for thermal degradation of anthocyanidin 3-glucosides. In addition, half-life values for p-coumaroylated anthocyanidin 3,5-glucosides of Violeta wine aged at 50 °C almost doubled those of their corresponding non-acylated derivatives. The latter result is suggested to be the main reason behind the relatively high resistance of Violeta wine towards the disappearance of anthocyanin under accelerated aging conditions. Finally, chromatic characteristics of Violeta wines did not significantly change their C* values during aging but L* and h* values increased as expected, the latter mainly due to higher increases of the yellow color component (b*) over lower decreases of the red color component (a*). These color changes were more drastic in the accelerated aged wines and the wine aged at 25 °C still maintained interesting color characteristics close to those of the control aged wine that did not change very much.     

Effects of high hydrostatic pressure and high temperature short time on antioxidant activity,antioxidant compounds and color of mango nectars

High hydrostatic pressure (HHP, 600 MPa/1 min) and high temperature short time (HTST, 110 °C/8.6 s) treatments of mango nectars were comparatively evaluated by examining their effects on antioxidant activity, antioxidant compounds, color, and browning degree (BD) immediately after treatments and during storage of 16 weeks at 4 and 25 °C. Steam blanching was used prior to HHP and HTST to inactive endogenous enzymes. Results showed that antioxidant capacity (FRAP assay), L-ascorbic acid, sodium erythorbate, total phenols, total carotenoids, the redness (a*), the yellowness (b*), and BD changed insignificant after HHP or HTST treatment. The lightness (L*) exhibited a significant decrease in HTST-treated mango nectars, while no significant changes in HHP-treated samples. After 16 weeks storage at 4 and 25 °C, there were significant changes in antioxidant activity, antioxidant compounds, color, and BD of mango nectars, whereas differences between HHP- and HTST-treated samples were not significant except for the decrease in L-ascorbic acid and sodium erythorbate, which was more pronounced in HHP-treated samples. Kinetic data of changes in L-ascorbic acid, sodium erythorbate, total phenols, and total carotenoids during storage fitted well into a combined model for both HHP- and HTST-treated samples.Industrial relevanceMango (Mangifera indica L.) is one of the important tropical fruits, and its processed products are of high commercial and economic importance. This research paper presents a comparison on HHP- and HTST-treated mango nectars, and also provides information about storage stability of antioxidant activity, antioxidant compounds, and color of mango nectars. The available data would provide technical support for the evaluation and application of HHP or HTST in the mango nectar industry, and also for the establishment of criteria for commercial production of high quality mango nectars with safety requirements.     

Quality characteristics of air-dried apple rings: Influence of storage time and fruit maturity measured by time-resolved reflectance spectroscopy

With the aim of studying the influence of maturity and of cold storage time on the quality characteristics of air-dried apple rings, 60 apples (cv Pink Lady^®) were measured at harvest by time-resolved reflectance spectroscopy (TRS) at 670 nm, ranked on the basis of decreasing absorption coefficient at 670 nm (μ_a670, increasing maturity) and hence classified based on the ranking order as less mature (LeM), medium mature (MeM,) and more mature (MoM). The sixty fruit were, then, randomized into 3 batches corresponding to 3 storage times (0, 3 and 5 months in normal atmosphere at +1 °C), and, at each storage time, 3 rings/fruit were air-dried at 80 °C up to a constant weight using a pilot air circulated drier. Quality characteristics of fresh fruit and of air-dried rings were analysed by ANOVA and PCA statistical analyses. Stored fruit compared to fruit at 0m were softer, had lower stiffness and energy-to-rupture, and higher soluble solids content (SSC), relative intercellular space volume (RISV) and L*_f. LeM class had lower SSC and dry matter, and the MoM class higher a*_f and lower b*_f than the other two classes. 3m-Apples showed the highest differences with respect to fresh ring in browning index (BI), total colour, chroma and hue, compared to fruit processed at 0m and 5m. Air-dried rings from less mature apples (i.e. those processed at 0m and of LeM class) had higher F_max, E_mod, E and BI than those from more mature fruits (i.e. those processed after storage and of MoM class). PCA underlined the positive relationship between mechanical characteristics of fresh fruit with those of dried rings and ring shrinkage, which were opposite to RISV, SSC and weight loss.     

A colorimetric study of oenin copigmented by procyanidins

A colorimetric method was used to analyse the influence of procyanidin structure on colour changes of malvidin 3‐O‐glucoside (oenin) solution resulting from copigmentation. The study was performed in hydroalcoholic citrate/phosphate buffer solution (120 g L^?1) at pH 3.6 and ionic strength 0.2 mol L^?1. Chromatic L*, a* and b* coordinates (CIELAB, D65/10° illuminant/observer condition) obtained from spectral curves recorded between 360 and 830 nm allowed the calculation of lightness L*, chroma C* and hue angle h_ab. In general, addition of copigment induced colour enhancement (loss of lightness and increased chroma). The prevailing parameters affecting colour changes were lightness and chroma for monomers and lightness and hue for procyanidins B5 and B8 (C4–C6 dimers). A small blueing effect was observed only for catechin monomer‐copigmented solutions. For procyanidin copigments, as the structural complexity of the copigment increased, the hue angle moved to yellower values. The ester gallate of dimer B2 produced the strongest modification of colour attributes of oenin solution. Copyright © 2006 Society of Chemical Industry     

Stability of microencapsulated Lactobacillus acidophilus and Lactococcus lactis ssp. cremoris during storage at room temperature at low aw

The effect of freeze drying or spray drying, the use of desiccants to maintain the low a_w and the period of storage (at 25 °C) of Lactobacillus acidophilus and Lactococcus lactis ssp. cremoris on survival, acid tolerance, bile tolerance, retention of surface hydrophobicity and retention of β-galactosidase was studied; an estimation of the maximum storage period was also carried out. Sodium caseinate, vegetable oil, glucose, mannitol and fructooligosaccharides were used as protectant of L. acidophilus and L. cremoris during freeze drying or spray drying and during subsequent storage. NaOH, LiCl and silica gel were used as desiccants during 10 weeks of storage of microencapsulated L. acidophilus and L. cremoris kept in an aluminum foil pouch. The results showed that mainly freeze dried L. acidophilus and L. cremoris kept in foil pouch containing NaOH (a_w 0.07) or LiCl (a_w 0.1) showed higher survival (89–94%) than spray dried bacteria kept under the same conditions (86–90%) after 10 weeks of storage (P = 0.0005). Similar results were also showed by acid tolerance, bile tolerance and surface hydrophobicity of freeze-dried or spray-dried L. acidophilus and L. cremoris. Silica gel was less effective in protecting the functional properties of microencapsulated L. acidophilus or L. cremoris with percentage of survival between 81 and 87% at week 10 of the storage. However, retention of β-galactosidase was only influenced by a_w adjusted by desiccators (P < 0.05). Based on forecasting using linear regression, the predicted storage period for freeze dried L. acidophilus, spray dried L. acidophilus and freeze dried L. cremoris kept in foil pouch containing NaOH would be 46, 42 and 42 weeks, respectively; while spray dried L. cremoris under LiCl desiccant would require 39 weeks to achieve minimum required bacterial population of 10⁷ CFU/g.     

Lamb meat quality of two breeds with protected origin designation. Influence of breed, sex and live weight

Lamb meat quality of two Portuguese products was examined. The influences of slaughter weight, sex and breed on eating quality were evaluated. Data were obtained from 72 lambs of two different breeds with protected designation origin. In accord with the normal slaughter weight in the region three classes were considered: A: 9–14 kg live weight; B: 14–19 kg live weight and C: 19–24 kg live weight. pH of M. longissimus thoracis et lumborum muscle (MTL) was measured 1 h and 24 h after slaughter. Meat colour was estimated in the M. longissimus thoracis et lumborum muscle (MTL) muscle on the 12th rib using the L* a* b* system. Shear force was evaluated 72 h after slaughter. Sensorial analysis was assessed by a trained taste panel of 12 members. The pH values found could be considered within the normal pH range, between 5.5 and 5.9. When the pH measurement was made 24 h after slaughter, the heavy lambs had significant higher value than the light lambs. In relation to colour variables, live weight, sex and breed had no effect on the red index (a*). Lightness (L) decreased with increasing live weight and the light lambs had higher yellow index (b*) than the heavier lambs. Shear force increased with live weight and the Bragançano breed had a greater mean shear force than the Mirandesa (7.8 vs. 6.8 kg/cm²). The heavy carcasses had more flavour intensity than the light ones. Mirandesa lambs had significantly lower values for toughness, stringy and odour intensity than Bragançana lambs.