Type of starter culture influences on structural and sensorial properties of low protein fermented gels

Organoleptic properties of skimmed milk fermented gels are progressively demanding to produce optimal quality yogurts. Chr‐Hansen trademark registered cultures were used to produce low‐protein (3.4%) gels to assess the ability to redesign the sensorial and textural properties with the choice of starter culture. Resulting gels were assessed for sensorial, textural, rheological, and microstructural properties and compared with a commercial control (4.5% protein). Mouth thickness, syneresis, firmness, elasticity, and consistency values were lower for polysaccharides‐producing cultures. Such cultures contributed to the higher creaminess and tended to give higher ropiness. Observed differences among microstructures of the gel were minute. Microstructural and rheological data corresponded and reflected the instrumental and sensory interpretations. Strong correlations were observed between sensory and instrumental data. Nonprobiotics cultures resulted in promising overall gel properties compared with probiotic cultures according to the principal component analysis. Yet probiotic cultures resulted in lower syneresis than nonprobiotic cultures. Thus, the choice of bacterial culture modifies the sensorial and textural properties of fermented gel with strong correlations, as a result of altered gel network formation with the production of polysaccharides. Inferior textural and sensorial quality aspects, particularly at low protein levels, have negative impact on consumer demand of low protein yogurts. Thus, we attempted to gain required gel textural and sensorial properties with a choice of starter culture with a low protein level. Resulting gel properties at lowered protein content with different starter cultures are not fully known. The present study compares the effect of probiotic and nonprobiotic starter cultures on gel properties, as gel texture and sensory properties are of great interest and thus not willing to be compromised. In addition, we examined the overall texture profile of studied cultures and correlate with sensory properties. Therefore, reducing protein level in milk and achieving required gel properties with the choice of appropriate starter culture is of great commercial interest as a cost‐cutting strategy to produce low‐cost optimum quality yogurt.     

Texture‐modified 3D printed dark chocolate: Sensory evaluation and consumer perception study

This study aimed to assess the preferences and perceptions of texture‐modified three‐dimensional (3D) printed chocolate through three measures: two tasting tests and one survey. In the first test, 30 semitrained panelists ranked their overall preference from among the three samples of chocolate printed in a honeycomb pattern with infill percentages (IPs) of 25, 50, and 100%. The panelists ranked the samples based on appearance and hardness. In the second test, the same panelists nominated one preference between a 3D printed sample (100% IP) and a cast commercial chocolate sample. Friedman test indicated that there was no significant difference in overall preferences for hardness although the panelists significantly preferred the appearance of samples with 25 and 50% over the 100% infill. Furthermore, there was no significant difference in preference between the cast and 100% infill samples. The texture data of the chocolate samples showed that a higher force was required to break the chocolate samples as the IP increased from 25% (20.4 ± 1.1 N) to 100% (54.4 ± 1.5 N). Also, the 3D printed chocolate (printed in 100% IP) was found to be less hard than that of casted chocolate. In the survey of consumer perceptions, a total of 244 participated and assessed the samples for their intricate design and novel technology concept through a questionnaire. While there was a general awareness of 3D printing technology among these participants, many were impressed with the application of 3D printing to chocolate, as this was the first time they had seen this. The results obtained from the sensory tests and consumer survey provided a useful insight into consumers' perception of 3D food printing and the 3D products design. This awareness will be beneficial to promote this technology in the food industry.     

Investigation of sweet potato starch as a structural enhancer for three‐dimensional printing of Scomberomorus niphonius surimi

Three‐dimensional printing (3DP) of surimi requires a structural modifier to achieve a stable construct. This work investigated the effect of addition of sweet potato starch (0–10% wt/wt) on the physical properties (rheological properties, gel strength, water‐holding capacity [WHC], and microstructural characteristics) of surimi gels and the 3D printed behavior of these gels. The results showed that as the starch content increased, the viscosity of the starch–surimi mixture decreased facilitating the flow of the surimi out of the printer nozzle. The surimi gel with 8% sweet potato starch concentration showed good gel strength (2,021.70 g mm), WHC (82.39%), microstructural characteristics, and less cooking loss (1.95%). A comparison of the traditional surimi preparation method with 3DP showed that the surimi gel prepared by a 3D printed construct was softer in gel strength (1,398.65 g mm) and lower in hardness (945.17 g) although showing slightly higher cooking loss (6.76%) and lower WHC (72.66 g) than the conventional product. The results suggest that sweet potato starch can be effectively used as a structural enhancer for 3DP complex‐shaped surimi.     

Effect of iron fortification on microstructural,textural, and sensory characteristics of caprine milk Cheddar cheeses under different storage treatments

In this study, we manufactured 3 types of caprine milk Cheddar cheese: a control cheese (unfortified) and 2 iron-fortified cheeses, one of which used regular ferrous sulfate (RFS) and the other used large microencapsulated ferrous sulfate (LMFS). We then compared the iron recovery rates and the microstructural, textural, and sensory properties of the 3 cheeses under different storage conditions (temperature and duration). Compositional analysis included fat, protein, ash, and moisture contents. The RFS (FeSO₄·7H₂O) and LMFS (with 700- to 800-μm large particle ferrous sulfate encapsulated in nonhydrogenated vegetable fat) were added to cheese curds after whey draining and were thoroughly mixed before hooping and pressing the cheese. Three batches of each type of goat cheese were stored at 2 temperatures (4°C and ?18°C) for 0, 2, and 4 mo. We analyzed the microstructure of cheese using scanning electron microscopy and image analysis software. A sensory panel (n = 8) evaluated flavors and overall acceptability of cheeses using a 10-point intensity score. Results showed that the control, RFS, and LMFS cheeses contained 0.0162, 0.822, and 0.932 mg of Fe/g of cheese, respectively, with substantially higher iron levels in both fortified cheeses. The iron recovery rates of RFS and LMFS were 71.9 and 73.5%, respectively. Protein, fat, and ash contents (%) of RFS and LMFS cheeses were higher than those of the control. Scanning electron microscopy analyses revealed that LMFS cheese contained smaller and more elongated sharp-edged iron particles, whereas RFS cheese had larger-perimeter rectangular iron crystals. Iron-fortified cheeses generally had higher hardness and gumminess scores than the control cheese. The higher hardness in iron-fortified cheeses compared with the control may be attributed to proteolysis of the protein matrix and its binding with iron crystals during storage. Control cheese had higher sensory scores than the 2 iron-fortified cheeses, and LMFS cheese had the lowest scores for all tested sensory properties.