Refrigerated clean room processing and packaging increases shelf life of refrigerated map packaged breaded products

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322 | PROCESADO Y CONSERVACIÓN DE ALIMENTOS

REFRIGERATED CLEAN ROOM PROCESSING AND

PACKAGING INCREASES SHELF LIFE OF REFRIGERATED MAP PACKAGED BREADED PRODUCTS

Marta Barón-Yusty, María Ros-Chumillas, Ginés Benito Martínez Hernández and Antonio López Gómez

Food Safety and Refrigeration Engineering Group, Department of Agricultural Engineering, Uni- versidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain.

Marta Barón-Yusty; Antonio López-Gómez

[email protected]; [email protected]

Abstract: The aim of this study was evaluate the effect of an innovative new technology (NT), in- cluding cyclodextrin (CD)-encapsulated extra-virgin olive oil (EVOO) within the breadcrumbs with subsequent baking in hot-air oven (frying-free), in combination with processing and packaging under clean-room conditions, on the product shelf-life. Two breaded products were used: chicken nuggets and croquettes. Prepared samples were packaged within a modified atmosphere of 30 % CO2 and 70 % N2 under either clean-room or normal conditions. Instrumental color, nutritional attributes, and microbiological characteristics were assessed during refrigerated storage at 4 °C for 14-21 days. Total oil uptake during processing of samples was reduced by 90 % when NT was used; and fiber content increased by 1.5-4 times. Processing and packaging under clean-room reduced bacterial populations and significantly extended the product’s shelf-life. In conclusion, the refrigerated shelf life of the studied breaded products was improved with this innovative new processing technology combined with packaging under cleanroom conditions.

Keywords: Reduced fat content, high fiber content, ultra-clean packaging, encapsulated EVOO, breadcrumbs.

1. INTRODUCTION

Consumers demand safe and high-quality products in terms of nutrition. These expectations linked with modern society’s healthy-lifestyle trends include innovative convenience fresh foods with minimal processing. In the 21^st-century novel technologies have been developed for food industries to satisfy both criteria (safety and quality) and among these are food reformulation, modified atmosphere packaging (MAP), cleanroom technology, active antimicrobial packaging, high pressure processing (HPP), pulsed electric field (PEF), ohmic heating, dielectric heating, microwave heating, ultrasound, etc. [1], [2].

Industries have valued positively cleanroom technology as it is validated as an effective stra- tegy to preserve food’s quality, as it does not affect nutritional values, and to ensure its safety, by maintaining clean-air and hygienic conditions in the processing and packaging areas by eliminating airborne microbiology [1]. The integration of cleanrooms with processing and packaging operations, such as MAP packaging is advantageous, as it has shown to provide shelf-life extension. Accordingly, extra virgin olive oil (EVOO) possess natural antimicrobial properties but its direct application in many products may lead to off-flavors [3]. Therefore, the utilization of EVOO encapsulated with cyclodextrins can be an alternative for antimicrobial activity in the formulation of breaded products.

The purpose of this study was to investigate the effect of clean room processing and MAP packaging of ready- to-cook breaded (with reformulated breadcrumbs) and fried-free cro-

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PROCESADO Y CONSERVACIÓN DE ALIMENTOS | 323

quettes and chicken nuggets, on the increase of shelf-life. The reformulation and cooking procedures of these breaded ready meals were also compared to traditional commercial products. The reformulation and new precooking procedure included (i) the introduction of microencapsulated EVOO on the breadcrumbs, which revealed to provide a sensorial similitude to traditional fried breaded products, and an antibacterial action during refrigerated storage, and (ii) precooking by infrared baking, avoiding the deep-fat frying procedure.

2. MATERIAL AND METHODS

2.1. Processing method of croquettes and chicken nuggets

Microencapsulated EVOO in α-CD was added (at 33 % and 0 % w/w) to corn breadcrumbs.

The microencapsulation of EVOO in α-CD was carried out according to [4]. These breadcrumbs were employed to prepare croquettes and chicken nuggets. Xanthan gum prepared in water at 0.25 % (w/w) was used as batter. Both, croquettes and chicken nuggets, were manually prepared under normal conditions (NC) or under clean-room conditions (UC) (ISO 5 or 100 class according to FED STD 209E) in a laminar flow cabinet at 12 °C. Croquettes were processed as per the guidelines of the patent ES2440092A1 [4]. Chicken nuggets were manufactured (3 x 3 x 1 cm size, and 8.07±1.57 g) out of skinless boneless chicken breast fillets.

After proper shaping, battering, and breading, products were precooked. Traditional breaded products were breaded with 0 % of encapsulated EVOO followed by a conventional deep-fat frying procedure (at 180 ºC 30 s in a 2 L volume fryer, model Professional 2; Taurus, Oliana, Spain). These traditional products were compared with those prepared by new technology (NT), which combined 33 % encapsulated EVOO and an oil-free baking with air at 150 °C for 5 min (in an oil-free fryer with 0.8-kg capacity, model FX100015; Tefal, Rumilly, France).

These ready to cook products were frozen at -20 ⁰C for 24 h, packaged (6 units/tray) as frozen in polyethylene trays (19.0 x 13.5 x 3.7 cm) in an automatic heat sealing machine (model Efaman, Efabin, Torre Pacheco, Murcia, Spain), in modified atmosphere (70 % N2, 30 % CO2).

Then, they were taken at 4 ⁰C in a cold room for shelf-life study (5-6 tray samplings every 3-4 days) during a set period of 14-21 days. Final cooking consisted of hot air baking at 180 ⁰C for 13 min (in a 35-L capacity hot air oven, model HBC36P753; Bosch, Germany) in the case of 33 % encapsulated EVOO (EVOO-α-CD samples), while control samples (0 % EVOO-β-CD) were deep-fat fried in sunflower oil at 180 ⁰C for 1.5 min.

2.2. Instrumental color

Color values in the CIELab color space (lightness, L*; redness, a*; yellowness, b*) of the ready to cook products (croquettes and chicken nuggets) were measured during the refrigerated storage period and before consumption using a portable colorimeter (Konica Minolta chro- mameter CR-400, Osaka, Japan) with a D-65 light source, 2º observer and measuring head of 8 mm. Determinations were carried out in triplicate.

2.3. Nutritional quality

Fat content was determined according to the ISO 17059 method [5] in a conventional Sox- hlet apparatus. Fiber content was quantified based on an enzymatic-gravimetric standard protocol AOAC 993.19.

2.4. Microbiological assay

Aliquots of 10 g of each sample were diluted with 90 mL of sterilized buffered peptone water and homogenized for 1 min in a sterile stomacher bag through a stomacher (IUL Mastica- tor 90002401, IUL S.A., Spain). Serial dilutions were performed and spread (yeast and molds) or pour-plated onto appropriate media. Plate Count Agar (PCA, Scharlau Chemie, Barcelona, Spain) incubated at 30 °C for 48 h was used to determine populations of mesophilic aerobic

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bacteria, and at 4 °C for 7 days for psychrophilic bacteria determination. Enterobacteriaceae counts were grown on Violet Red Bile Dextrose Agar (Scharlau Chemie, Barcelona, Spain) at 37 °C for 48 h. Psychrophilic bacteria were determined by incubating in PCA at 4 °C for 7 days. Rose Bengal Agar (Scharlau Chemie, Barcelona, Spain) was used to enumerate molds and yeast (25 ºC for 5-7 days). All plates were performed in triplicate and the results were expressed as log of colony forming units (CFU) per gram of product (log CFU g⁻¹).

2.5. Statistical analysis

Treatment differences were analyzed at a 0.05 level of probability with the R studio softwa- re. A unidirectional analysis of variance (ANOVA) was tested followed by a Tukey HSD test.

Results were expressed as mean ± standard deviation.

3. RESULTS & DISCUSSION

3.1. Color

Results show that there are significant differences (p < 0.05) between the values of L* and a*

of baked breaded products fortified with 33 % EVOO-α-CD and those prepared as traditional product (0% EVOO-α-CD + frying) (data not shown). Despite these significant differences in color, the color parameter of all treatments was positively valued by the panelists, and no sample was rejected as unsuitable for marketing due to a color defect. This results agree with those obtained by [6], since the highest values of a*, as well as the lowest values of L*, are obtained in the breaded product subjected to traditional frying. These values would have been desirable in the new methodology (33 % EVOO-α-CD + oil-free frying), but they were expected since it was not a conventional frying. The same occurred in the study by [7]

by substituting the pre-frying of nuggets in oil for a “frying” in the microwave. The proposed technology gives rise to a more yellow color than the golden-brown color characteristic of conventional breaded products fried in oil.

3.2. Nutritional content

Nutritional content evaluation includes fat and fiber content, and oil absorbed after final baking/frying (Table 1) of croquettes and chicken nuggets. The incorporation of EVOO-α-CD in the breading phase resulted in slight changes in these parameters. The use of EVOO-α-CD had a significant effect on fiber content. Nuggets and croquettes fortified with encapsulated EVOO presented by 1.5-4 times more soluble fiber than control samples.

The total fat/100 g of a raw croquette (intrinsic fat) amounts to 4.09 %. The conventional system of manufacturing and preparing for consumption of croquettes (0 % EVOO-α-CD + frying) adds to this last value, 150.03 % more total fat/100 g (10.22%); while fortified croquettes (with EVOO-α-CD) combined with a baking treatment presents 4.48 % total fat/100 g, an increasement of 9.07 % of a raw croquette. Oil absorbed reduction between treatments rea- ches a value of 93.54 %. This finding is in agreement with what [8] reported when comparing baking and frying procedures on the fat content of green or red cabbage or their aqueous extracts based croquettes. According to these researchers, higher values of crude fat were found on fried croquettes (11.20 ± 0.27 % to 17.78 ± 0.43 %) compared to baked samples (3.07 ± 0.25 % to 3.96 ± 0.29 %). Fat reduction can be ascribed to the cooking procedure employed, as similar results were found. Nevertheless, in our study baked croquettes show higher values, which indicates that the introduction of EVOO-α-CD increases slightly the fat content in the product as it was aimed for good sensorial acceptation.

Chicken nuggets fat content values followed the same tendency as croquettes. Baked EVOO- α-CD enriched samples were found much lower in fat values. Pre-fried chicken nuggets had the highest fat content (20.66 ± 2.98 g/100 g), while baked chicken nuggets breaded with 33

% EVOO-α-CD had the lowest (2.95 ± 0.90 g/100 g). As for croquettes, oil absorbed reduction

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between treatments reached a value above 90 %. Similar values have been reported by [9]

for pre-fried chicken nuggets, up to 22.7 ± 0.1 g/100 g. Researchers reported total fat mean value was dependent on the cooking procedure, and fat values increased in the following order: baked in the oven < pre-fried < fried.

Table 1. Nutritional content of croquettes and chicken nuggets breadcrumbed with 0 or 33 % EVOO-α- CD, fried or oil-free fried, respectively. Values given are averages of three replicate samples ± standard

deviations.

Nutritional content

(g/100g) Breading Cooking procedure Ready meal

Croquette Chicken nugget

Fat content Raw product 4.09 ± 0.92^a 1.16 ± 0.28^a

0% EVOO-α-CD Deep-fat frying 10.22 ± 1.51^b 20.66 ± 2.98^b 33% EVOO-α-CD Oil-free frying 4.48 ± 1.07â 2.95 ± 0.90^c Oil absorbed 0 % EVOO-α-CD Deep-fat frying 6.13 ± 1.77â 19.50 ± 2.99â

33 % EVOO-α-CD Oil-free frying 0.40 ± 1.41^b 1.80 ± 0.94^b Fiber content 0% EVOO-α-CD Deep-fat frying 1.0 ± 0.05^a 0.3 ± 0.05^a

33% EVOO-α-CD Oil-free frying 1.5 ± 0.05^b 1.2 ± 0.05^b

a-c Different lowercase letters (superscripts) within each column indicate significant differences (p < 0.05).

3.3. Microbiological results

The microbial quality decay of EVOO-α-CD enriched breaded products was evaluated on croquettes and nuggets manufactured under normal and ultra-clean conditions, by monitoring the viable cell concentration of the main spoilage microbial groups such as mesophilic bac- teria, psychrophilic bacteria, Enterobacteriaceae, yeasts and molds. Data of each analyzed microbial group of both croquettes and nuggets samples are shown in Figures 1 and 2, respectively.

CYTEF 2022 − XI Congreso Ibérico | IX Congreso Iberoamericano de Ciencias y Técnicas del Frío Cartagena, España, 17-19 abril, 2022

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Figure 1. Bacterial counts over 21 days of refrigeration at 4 °C for (solid lines) normal and, (dashed lines) cleanroom processed, and packaged croquettes enriched with 0% (■) or 33% EVOO-α-CD (■). Samples with 0% EVOO-α-CD are pre-fried (180 ºC/30 s) and samples with 33% EVOO-α-CD have been oil-free fried (baked at 150 °C 5 min).

Total bacterial count (log cfu/g) is shown for (a) total aerobic mesophiles, (b) Enterobacteriaceae, (c) psychrophiles, (d) yeasts, and (e) molds. Values are expressed as mean ±SD, where error bars represent standard deviations of the mean value.

The above evidence suggests that the addition of 33% EVOO-α-CD acted in a combined way with the baking cooking treatment applied to delay the growth of all microbial groups analyzed for both ready to cook meals (croquettes and nuggets). As can be inferred, 0% EVOO-α-CD samples exceed cell load selected threshold limit (10⁶CFU/g) at day twelfth for both croquettes and nuggets, whilst 33% EVOO-α-CD croquettes samples manufactured under normal conditions maintained it below the permissible limit for up to 21 days. Nuggets breaded with 33% EVOO-α-CD did not exceed microbial acceptability level during the entire observation period. Best performance was recorded under clean room conditions, as they were the most efficient conditions in holding up microbial proliferation, regardless of the treatment employed. Nevertheless, these data highlight that control samples manufactured under clean room, although decrease those manufactured under normal conditions showed an increase in total bacterial count compared to 33% EVOO-α-CD samples manufactured under clean room conditions.

Figure 1. Bacterial counts over 21 days of refrigeration at 4 °C for (solid lines) normal and, (dashed lines) cleanroom processed, and packaged croquettes enriched with 0% (■) or 33% EVOO-α-CD (■).

Samples with 0% EVOO-α-CD are pre-fried (180 ºC/30 s) and samples with 33% EVOO-α-CD have been oil-free fried (baked at 150 °C 5 min). Total bacterial count (log cfu/g) is shown for (a) total aerobic mesophiles, (b) Enterobacteriaceae, (c) psychrophiles, (d) yeasts, and (e) molds. Values are

expressed as mean ±SD, where error bars represent standard deviations of the mean value.

The above evidence suggests that the addition of 33 % EVOO-α-CD acted in a combined way with the baking cooking treatment applied to delay the growth of all microbial groups

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analyzed for both ready to cook meals (croquettes and nuggets). As can be inferred, 0 % EVOO-α-CD samples exceed cell load selected threshold limit (10⁶ CFU/g) at day twelfth for both croquettes and nuggets, whilst 33 % EVOO-α-CD croquettes samples manufactured under normal conditions maintained it below the permissible limit for up to 21 days. Nuggets breaded with 33 % EVOO-α-CD did not exceed microbial acceptability level during the entire observation period. Best performance was recorded under clean room conditions, as they were the most efficient conditions in holding up microbial proliferation, regardless of the treatment employed. Nevertheless, these data highlight that control samples manufactured under clean room, although decrease those manufactured under normal conditions showed an increase in total bacterial count compared to 33 % EVOO-α-CD samples manufactured under clean room conditions.

CYTEF 2022 − XI Congreso Ibérico | IX Congreso Iberoamericano de Ciencias y Técnicas del Frío Cartagena, España, 17-19 abril, 2022

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Figure 2. Bacterial counts over 14 days of refrigeration at 4 °C for (solid lines) normal and (dashed lines) cleanroom processed, and packaged chicken nuggets enriched with 0% (■) or 33% EVOO-α-CD (■). Samples with 0% EVOO- α-CD are pre-fried (180 ºC/30 s) and samples with 33% EVOO-α-CD have been oil-free fried (baked at 150 °C/5 min). Total bacterial count (log cfu/g) is shown for (a) total aerobic mesophile, (b) Enterobacteriaceae, (c) psychrophiles, (d) yeasts, and (e) molds. Values are expressed as mean ±SD, where error bars represent standard deviations of the mean value.

4. CONCLUSIONS

It is concluded that oil-free fried 33% EVOO-α-CD croquettes and nuggets resulted in better nutritional and microbiological attributes than conventional formulated and fried croquettes and nuggets. Significant differences were found in color, although both treatments were positively acceptable. Clean room processing and packaging prolonged shelf life for both products and cooking procedures. Overall, very positive results were acquired for the introduction of 33% EVOO-α-CD with an oil-free frying procedure and it could be used for commercial applications in combination with clean room processing and packaging.

FUNDING. This research has received funding from the Centre for the Development of Industrial Technology (CDTI, Madrid, Spain) through the project “New process technologies for healthy breaded products (Ref. IDI- 20190627)”.

REFERENCES

[1] Gupta A, Kaur M, and Kaur A. Cleanroom Technology and Its Application in Food Proceesing. Novel Food Processing Technologies, 2017 1:323-357 2017.

[2] Buendía−Moreno L, Sánchez−Martínez MJ, Antolinos V, Ros−Chumillas M, Navarro−Segura L, Soto−Jover S, Martínez−Hernández GB, López−Gómez A. Active cardboard box with a coating including essential oils entrapped within cyclodextrins and/or hallosyte nanotubes. A case study for fresh tomato storage, Food Control, 2020, 207:106763

[3] Medina E, Romero C, Brenes M, and De Castro A. Antimicrobial activity of olive oil, vinegar, and various beverages against foodborne pathogens, J. Food Prot., 2007 70(5):1194–1199.

[4] López-Gómez A, Soto-Jover S, and Boluda-Aguilar M, “Composición y método de elaboración de Figure 2. Bacterial counts over 14 days of refrigeration at 4 °C for (solid lines) normal and (dashed lines) cleanroom processed, and packaged chicken nuggets enriched with 0 % (■) or 33 % EVOO-α- CD (■). Samples with 0 % EVOO-α-CD are pre-fried (180 ºC/30 s) and samples with 33 % EVOO-α- CD have been oil-free fried (baked at 150 °C/5 min). Total bacterial count (log CFU/g) is shown for (a) total aerobic mesophile, (b) Enterobacteriaceae, (c) psychrophiles, (d) yeasts, and (e) molds. Values

are expressed as mean ±SD, where error bars represent standard deviations of the mean value.

4. CONCLUSIONS

It is concluded that oil-free fried 33 % EVOO-α-CD croquettes and nuggets resulted in better nutritional and microbiological attributes than conventional formulated and fried croquettes and nuggets. Significant differences were found in color, although both treatments were positively acceptable. Clean room processing and packaging prolonged shelf life for both products and cooking procedures. Overall, very positive results were acquired for the introduction of 33 % EVOO-α-CD with an oil-free frying procedure and it could be used for commercial applications in combination with clean room processing and packaging.

FUNDING

This research has received funding from the Centre for the Development of Industrial Te- chnology (CDTI, Madrid, Spain) through the project “New process technologies for healthy breaded products (Ref. IDI- 20190627)”.

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REFERENCES

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[2] Buendía−Moreno L, Sánchez−Martínez MJ, Antolinos V, Ros−Chumillas M, Navarro−Segura L, Soto−

Jover S, Martínez−Hernández GB, López−Gómez A. Active cardboard box with a coating including essential oils entrapped within cyclodextrins and/or hallosyte nanotubes. A case study for fresh tomato storage, Food Control, 2020, 207:106763

[3] Medina E, Romero C, Brenes M, and De Castro A. Antimicrobial activity of olive oil, vinegar, and various beverages against foodborne pathogens, J. Food Prot., 2007 70(5):1194–1199.

[4] López-Gómez A, Soto-Jover S, and Boluda-Aguilar M, “Composición y método de elaboración de alimentos empanados con baja absorción de aceite durante la fritura,” ES2440092A1, 2013.

[5] ISO 17059:2007 - Oilseeds — Extraction of oil and preparation of methyl esters of triglyceride fatty acids for analysis by gas chromatography (Rapid method).

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[7] Albert A, Salvador A, Hough G, and Fiszman S, Influence of Outer Layer Formulation on the Sensory Properties of Microwaved Breaded Nuggets, Int. J. Food Prop, 2013, 17(4): 829-841.

[8] Ashfaq F, Butt MS, Bilal A, Tehseen S, and Suleria HAR. Effect of cabbage or its aqueous extract incorporated croquettes on chemical composition and storage stability in relation to antioxidant potential and sensory profile, J. Food Process. Preserv, 2020, 44(1): 14291.

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