Journal of Food Processing and Preservation最新文献

The present work deals with the chemical properties of vegetable oils commonly used for deep-frying, for example, sunflower, corn, cotton, canola, and olive oils. Ten deep-frying cycles were carried out for 20 min each. Oil degradation was measured by peroxide values (PVs) and was highly correlated with the presence of conjugated-diene and conjugated-triene structures. Frying cycles caused two alternative reactions, which both impacted the PV. In one reaction, there was an increase in PV with the oxidation of the unsaturated bonds, and in the second stage, there was a decrease in the cleavage of the double-bond oxide. Additionally, the point of returns (PRs) and activation energy (Ea) were determined for the two stages. The PRs were eight cycles for olive and corn, five cycles for canola, four cycles for sunflower, and three cycles for cotton oil. In terms of ER, the olive and cotton oils had the highest ER and were most resistant to decomposition, and the associated activation energy formation of peroxide decomposition products. The corn oil was the least resistant to decomposition. In addition, this work demonstrated a novel analytical technique that showed the correlation between the total value of conjugated diene-triene structures and PV, using a titration method. The correlation was high confidence for the regression, recovery, and U⁹⁵. This significant correlation is useful for measuring the PV of oils subjected to other processes.

Date press cake (DPC) is a by-product of date syrup (also known Dips) production with high nutritional content. However, it is still underutilized owing to the lack of knowledge about its health benefits and possible food applications. Therefore, the aim of the study was to prepare low-calorie fibre-rich functional cookies fortified with DPC. Different additions of DPC (5% and 10% on wheat flour basis) were added while sugar was reduced by 25% and 50% and replaced by 0.39 and 0.65 g Stevia, respectively. Cookies were analysed for their physicochemical and sensory attributes. The obtained results showed that moisture content, ash, and dietary fibre content significantly (p < 0.05) increased with increasing DPC amount, while sucrose content decreased significantly in treatments compared to the control. In addition, the hardness of 10% DPC-enriched cookies with 50% sugar reduction was slightly significantly higher than the control, while other treatments were not significantly different. The addition of DPC significantly decreased both L^∗ and b^∗, while increasing a^∗ of cookies. The results also revealed that the diameter, thickness, and spread ratio of the DPC-enriched cookies did not significantly differ from those of the control sample. On the other hand, the inclusion of DPC and Stevia significantly lowered the weight before baking of cookies, while the baking loss did not significantly change, apart from cookies with 5% DPC and 50% sugar reduction which showed a slight significant increase. The sensory evaluation results showed that cookies with 10% DPC inclusion and 25% sugar reduction received the highest appearance, texture, flavour, and overall acceptability scores compared to the control. However, the differences were not significant. These results indicate that the incorporation of DPC as a low-cost fibre-rich ingredient in cookies, along with the sugar reduction and Stevia substitution, improved the fibre content and nutritional value of cookies without compromising their physical or sensory attributes.

In this study, five drying methods (hot air drying [HD], light wave drying [LD], far infrared drying [FID], freeze drying [FD], and heat pump drying [HPD]) were applied to dry Sargassum fusiforme. The color, rehydration rate (RR), and volatile flavor substances of dried S. fusiforme were compared and analyzed, and the content, molecular weight (Mw), monosaccharide composition, and antioxidant activity of dried S. fusiforme crude polysaccharides (SFCPs) were analyzed. The results showed that S. fusiforme dried by different drying methods showed different colors. FD produced S. fusiforme with better RR (p < 0.05). The Mw of the SFCPs were 624.06, 534.86, 683.00, 1077.13, and 981.91 kDa, respectively, for HD, LD, FID, FD, and HPD. The Mw and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging rates of SFCP-FD were greater than those of the remaining four drying methods; however, the ABTS (2,2 ^′-azobis-3-ethylbenzothiazoline-6-sulfonic acid) and OH (hydroxyl) radical scavenging rates were highest in the SFCP-HPD. GC-IMS analysis showed that the drying method affected the content and composition of volatile flavor compounds. Principal component analysis (PCA) analysis indicated that the flavors of dried S. fusiforme were quite different from that of fresh S. fusiforme, and the flavors of HD, LD, and FID were similar, while the flavors of FD and HPD were similar.

This research was aimed at investigating the effect of edible coatings based on the combination of carboxymethyl cellulose (CMC) and soy protein isolate (SPI) containing 0.0%, 1.0%, 2.0%, and 3.0% w/v of nanoencapsulated pistachio green peel extract (PGPE) on the chemical and microbiological properties of raw pistachio of Kale Ghoochi variety during 18 weeks of storage at 27 ± 1°C. Moisture content (MC), acid value (AV), peroxide value (PV), total phenol content (TPC), total viable count (TVC), and total fungi count (TFC) were tested at 21-day intervals. PGPE contains phenolic compounds (48.73 mg GAE/g) with antioxidant activity (IC₅₀ = 10.83) which increased MC (19.51%) and TPC (75.62%) of coated samples with 3% PGPE compared with control, whereas AV (41.12%), PV (53.16%), TVC (44.64%), and TFC (35.01%) reduced (p < 0.05). The results of this research suggested that the edible coatings based on the combination of CMC and SPI containing nanoencapsulated PGPE have the ability to reduce the oil oxidation reactions and microbial growth in raw pistachio. Therefore, the concentration of 2.0% nanoencapsulated PGPE due to its better properties can be used to extend the shelf life of raw pistachio.

This study determined whether natural preservatives, when used as substitutes for sulfur dioxide (SO₂) in Boerewors, influenced water activity (a_w), pH, and moisture content; microbial and sensory quality; and the lipid oxidative and color stability in Boerewors models. The inclusion of sulfur dioxide at 0.035% (positive control), formulation without preservatives (negative control); protective cultures (PrC1 and PrC2), containing lactic acid bacteria; and plant extract blends (KD1 and KD2), containing rosemary and acerola extracts and buffered vinegar, were evaluated. The use of KD2 increased pH on Days 0 and 6, but the increased pH did not affect the microbial preservative effect. The a_w of the treatments was stable over 6 days and therefore also did not have an influence on the microbial preservative effect of the natural preservatives. Both plant extract preservatives (KD1 and KD2) increased the oxidative stability of lipids more than any other treatment, including the positive control. The microbial stability results were inconclusive because of the protective cultures, which increased the total bacteria count. The counts of coliform and Enterobacteriaceae, Escherichia coli, and Staphylococcus aureus were analyzed, but significant differences between the treatments were not observed. KD1, which contained rosemary plant extract, maintained the lowest TBC at the same level as the positive control but had a slightly lower redness score. Treatments had no effect on sensory evaluation. The use of KD1 and KD2 plant preservatives proofed to be worthy as replacers of SO₂ in Boerewors. This manuscript contains research data that formed part of an M.Sc. thesis. This manuscript also contains materials and methods that were used in a Ph.D. thesis where salt reduction in South African meat products was evaluated.

Foxtail millet is a type of minor millet that has nutritional-rich characteristics. The bran layer in millets contains a considerable amount of antinutritional properties, and grain/flour/product spoilage occurs due to fat in the bran layer. Therefore, the removal of bran from millets can enhance their shelf life. Bran removal from foxtail millet is challenging because of its tiny size. Hence, the study targeted optimizing polishing process parameters for foxtail millet. The effect of process variables such as grain moisture content (8%–16% w.b.), emery roller speed (800–2400 rpm), and polishing time (1–8 min) on polishing characteristics (degree of polishing, head yield, middling yield, and broken content) and proximate composition (protein, fat, crude fiber, ash, and carbohydrate contents) of foxtail millets was studied using the central composite rotatable design (CCRD). Emery roller speed and polishing time significantly affected all responses (p < 0.01). In contrast, grain moisture content had a significant effect only on the degree of polishing (p < 0.05), head, and middling yields (p < 0.01). A numerical optimization technique was adopted to optimize the process parameters of the polisher. The optimum operating conditions were 10% grain moisture content, 1650 rpm of emery roller speed, and 2 min of polishing time. A validation study conducted at optimized conditions revealed no significant difference between the predicted and actual values of responses and considerably less broken content (9.26%). The results of the present study indicate that machinery modified and processes optimized during the study are fairly accepted and can be used to upscale the machine for industrial use.

Traditional methods of separating defective cucumbers are inherently labor-intensive and time-consuming. However, with the emergence of intelligent farming practices, deep learning (DL) algorithms, particularly in the fields of image processing and machine vision, have demonstrated significant potential to address this challenge. The main objective of this research study is to develop a DL-based algorithm capable of classifying cucumbers into three distinct categorical groups based on their visual characteristics: defective, curved, and sound (straight green). For this purpose, in addition to inspect the more accurate InceptionResNetV2 as a transfer learning method, the modified convolutional neural network (CNN) (MCNN) incorporating global average pooling (GAP) was proposed to streamline the architecture and minimize trainable parameters. The results demonstrate that the accuracy of CNN with the GAP layer outperforms the fully connected (FC) layer (FCL). The accuracies for the proposed CNN with GAP, proposed CNN with FCL, and InceptionResNetV2 were 94.14%, 92.92%, and 91.21%, respectively, highlighting the efficiency of the CNN with GAP in cucumber classification and its potential to replace conventional grading methods. The overall results indicated that the implementation of dropout did not yield any improvements for the developed models. Rather, the best performance of the CNNs was achieved when utilizing 64 neurons in the hidden layer.

The research is aimed at addressing concerns regarding the health implications of increased cola consumption by developing a healthier alternative. This was achieved by replacing phosphoric acid with organic acidulants (citric acid (CA), lactic acid (LA), and tartaric acid (TA)) and enriching the drink with calcium gluconate salt. Response surface methodology (RSM) was employed as a statistical optimization tool to ensure the formulation met predefined criteria for physicochemical and sensory parameters. The optimized cola drink formulation consisted of 0.07% CA, 0.05% TA, and 0.04% LA, along with calcium gluconate. The physicochemical analysis revealed a pH of 3.36, an acidity of 7.72%, a reducing sugar (glucose) content of 4.46%, and a Brix value of 12.7°. Sensory evaluation indicated high overall acceptability with a hedonic score of 7.08, suggesting that the optimized cola drink with improved qualitative characteristics could serve as a desirable option for consumers seeking healthier beverage choices. Further studies could explore its long-term health effects and market feasibility.

Garlic production and consumption are rapidly increasing due to its recognized health benefits. Peeling garlic before consumption is one of the most important basic operations. The garlic cloves must have the thin, inedible layer of membranous skin peeled off. The peeled garlic cloves are also used to make value-added and long shelf life products such as garlic sauce, garlic pickle, dehydrated garlic (cips-granul-powder), garlic extract, garlic tablet, and garlic oil. For this purpose, a pneumatic garlic peeling machine, which has two peeling units, has been developed and tested. Trials were carried out with 5, 7, and 9 bar peeling air pressure; 10, 15, and 20 s peeling time; and 0.2, 0.4, 0.6, 0.8, and 1.0 s loading time. The peeled garlic percentage was between 49.2% and 99.8%, and the machine efficiency was between 32.8 and 100.6 kg/h. Since the amount of unpeeled garlic coming out of the machine will significantly increase the labor required for separation, 96.4 kg/h peeled and 1.4 kg/h unpeeled garlic amounts with the parameters 9 bar peeling air pressure, 0.6 s loading time, and 10 s peeling time were found to be the most successful result. If both units are operated together, the total machine efficiency will be about 200 kg/h. Compared to manual peeling, about 99.6% labor saving is achieved. Compared to other mechanic and pneumatic garlic peelers in the literature, it has been determined that they can be used easily because the percentage of peeled garlic and machine efficiency is relatively high.

This study is aimed at producing extrudates using sorghum and orange-fleshed sweet potato (OFSP) flour in varying ratios (90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, and 20:80), with extrudates made from 100% sorghum serving as the control. The puffed snacks’ physicochemical, nutritional, textural, and sensory qualities were assessed, and the obtained data were analyzed through ANOVA. Our findings revealed notable variations in the physicochemical properties of the puffed snacks, showing a decrease in moisture, fat, protein, and crude fibre content as the percentage of OFSP flour increased. Furthermore, increased substitution of sorghum flour with OFSP in the extrudates led to a corresponding rise in vitamin A, B₁, and C levels from 0.24, 0.15 and 0.21 mg/100 g in the control to 1.30, 0.19, and 1.82 mg/100 g in the extrudates made from 20% sorghum. More so, samples with increased OFSP content were preferred regarding springiness, chewiness, gumminess, and cohesiveness, whereas those with elevated percentages of sorghum received higher likeness for adhesiveness and stringiness. Extruded samples containing 80% and 90% sorghum levels received the highest overall acceptance ratings of 7.15 and 7.18, respectively. The research results are essential for the food industry to produce nutritious extrudates with appealing sensory characteristics and textures.